Shrink material and pattern forming process

ABSTRACT

A shrink material is provided comprising a specific polymer and a solvent containing an anti-vanishing solvent. A pattern is formed by applying a resist composition comprising a base resin and an acid generator onto a substrate to form a resist film, exposing, developing in an organic solvent developer to form a negative resist pattern, applying the shrink material onto the pattern, and removing the excessive shrink material with an organic solvent for thereby shrinking the size of holes and/or slits in the pattern.

CROSS-REFERENCE TO RELATED APPLICATION

This non-provisional application claims priority under 35 U.S.C. §119(a)on Patent Application Nos. 2014-248080 and 2015-077690 filed in Japan onDec. 8, 2014 and Apr. 6, 2015, respectively, the entire contents ofwhich are hereby incorporated by reference.

TECHNICAL FIELD

This invention relates to a shrink material for shrinking the size offeatures in a resist pattern and a pattern forming process using theshrink material.

BACKGROUND ART

While the effort to reduce the pattern rule is in rapid progress to meetthe recent demand for higher integration level and operating speed ofLSIs, the photolithography is on widespread use. The photolithographyhas the essential limit of resolution determined by the wavelength of alight source. One micropatterning approach to go beyond the limit ofresolution is by combining ArF excimer laser immersion lithography withdouble patterning. One typical version of double patterning islitho-etch-litho-etch (LELE) process involving forming a pattern viaexposure, transferring the pattern to a hard mask on a substrate byetching, effecting second exposure at a half-pitch shifted position, andetching the hard mask. This process has the problem of misalignmentbetween two exposures or overlay error. Another version of doublepatterning is self-aligned double patterning (SADP) process involvingthe steps of transferring a resist pattern to a hard mask, growing afilm on opposite sides of hard mask features, and leaving sidewalls offilm for thereby doubling pattern size. The SADP process needs exposureonly once and mitigates the problem of overlay error. To simplify theprocess, a modified version of the SADP process of forming a siliconoxide film on sidewalls of resist pattern features as developed ratherthan sidewalls of hard mask features for thereby doubling pattern sizeis also proposed. Since the SADP process is successful in reducing thepitch of line pattern to half, the pitch can be reduced to ¼ byrepeating the SADP process twice.

Not only shrinking of line patterns, but also shrinking of hole patternsis necessary. Unless the hole pattern is shrunk, shrinkage over theentire chip is incomplete. One known method of shrinking a hole patternis RELACS® method described in Patent Document 1. This method intends toreduce the size of a hole pattern by coating a resist pattern asdeveloped with a water-soluble material containing a crosslinker, andbaking the coating to form a crosslinked layer on the resist surface forcausing the resist pattern to be thickened. Patent Document 2 describesa shrink material comprising an amino-containing polymer or polyamine,which bonds to the resist surface via neutralization reaction withcarboxyl groups on the resist surface, for thereby thickening the resistfilm. It is also proposed in Non-Patent Document 1 to shrink a holepattern by utilizing the direct self-assembly (DSA) of a blockcopolymer.

Shrinkage by the RELACS® method has the problem that since a crosslinkerbecomes active with an acid catalyst within resist, the size of holes isnon-uniform after shrinkage if acid diffusion is non-uniform. In theshrink method based on neutralization and bonding of amino polymer, thepattern is thickened as direct reflection of irregularities on theresist surface so that dimensional variations of the resist pattern asdeveloped and dimensional variations after shrinkage are identical. Theshrink method utilizing the DSA function of a block copolymer hasadvantages including an increased amount of shrinkage and a minimaldimensional variation after shrinkage, but some problems. Namely, if theDSA is applied to holes of different size, shrinkage cannot be inducedfor those holes of the size that causes a contradictory assembly ofblock copolymer. If the DSA is applied to a trench pattern, shapedeformation becomes a problem, for example, a plurality of hole patternsare formed.

There is a need for a shrink material which can shrink a hole patternwithout changing the shape of the resist pattern, and improve thedimensional variation and edge roughness (LWR) of the resist patternafter development.

CITATION LIST

-   -   Patent Document 1: JP-A H10-073927 (U.S. Pat. No. 6,579,657)    -   Patent Document 2: JP-A 2008-275995 (US 20100119717)    -   Patent Document 3: JP-A 2007-293294    -   Non-Patent Document 1: Proc. SPIE Vol. 8323 p83230W-1 (2012)

SUMMARY OF INVENTION

As discussed above, the method of applying a RELACS® material ofcrosslink type or neutralizing reaction-mediated bond type onto a resistpattern causes no pattern deformation, but fails to reduce thedimensional variation of the resist pattern. Patent Document 3 proposesa shrink material of alkaline aqueous solution treatment type applied toa positive tone resist pattern resulting from alkaline development. Withrespect to the shrinkage of a hole pattern with a narrow pitch, thisshrink material fails to gain a sufficient amount of shrinkage and toreduce dimensional variation.

An object of the invention is to provide a shrink material which whencoated onto a hole resist pattern as developed, can shrink the hole sizewhile improving dimensional variation; and a pattern forming processusing the same.

Seeking a shrink material capable of effectively shrinking a resistpattern as developed, the inventors have found that by forming a resistfilm based on a base resin having an acid labile group-substitutedcarboxyl group and an acid generator, forming a negative tone resistpattern therefrom via exposure and organic solvent development, coatingthe resist pattern with a shrink material comprising a specific polymerand a solvent containing an anti-vanishing solvent, baking, and removingthe excessive shrink material with an organic solvent, the size of holesand/or slits in the resist pattern can be shrunk in a controlled manner.

In one aspect, the invention provides a shrink material comprising apolymer and a solvent containing an anti-vanishing solvent which doesnot cause a resist pattern after development to vanish, the polymercomprising recurring units of at least one type selected from unitshaving the formulae (1a) and (1b).

Herein A is a single bond or a C₁-C₁₀ alkylene group which may containan ethereal oxygen atom at an intermediate of the chain; R′ is hydrogen,fluorine, methyl or trifluoromethyl; R² is each independently hydrogen,halogen, an optionally halo-substituted, straight, branched or cyclic,C₂-C₈ acyloxy group, an optionally halo-substituted, straight, branchedor cyclic, C₁-C₆ alkyl group, or an optionally halo-substituted,straight, branched or cyclic, C₁-C₆ alkoxy group; L is hydrogen, astraight, branched or cyclic, C₁-C₁₀ monovalent aliphatic hydrocarbongroup which may contain an ethereal oxygen atom, carbonyl moiety orcarbonyloxy moiety at an intermediate of the chain, or an optionallysubstituted, monovalent aromatic ring-containing group; Z bonds with thecarbon atom to form a C₅-C₁₅ alicyclic group; R^(x) and R^(y) are eachindependently hydrogen or a straight, branched or cyclic, C₁-C₁₅ alkylgroup which may be substituted with a hydroxyl or alkoxy moiety, atleast one of R^(x) and R^(y) being a cyclic C₅-C₁₅ alkyl group; f is aninteger of 1 to 3, s is an integer of 0 to 2, a is equal to (5+2s−f),and m is 0 or 1.

Preferably the polymer further comprises recurring units having theformula (2).

Herein B is a single bond or a C₁-C₁₀ alkylene group which may containan ethereal oxygen atom at an intermediate of the chain; R¹ is asdefined above; R³ is each independently hydrogen, halogen, an optionallyhalo-substituted, straight, branched or cyclic, C₂-C₈ acyloxy group, anoptionally halo-substituted, straight, branched or cyclic, C₁-C₆ alkylgroup, or an optionally halo-substituted, straight, branched or cyclic,C₁-C₆ alkoxy group; g is an integer of 0 to 3, t is an integer of 0 to2, b is equal to (5+2t−g), and n is 0 or 1.

Preferably the polymer further comprises recurring units having theformula (3).

Herein C is a single bond or a C₁-C₁₀ alkylene group which may containan ethereal oxygen atom at an intermediate of the chain; R¹ is asdefined above; R⁴ is each independently hydrogen, halogen, an optionallyhalo-substituted, straight, branched or cyclic, C₂-C₈ acyloxy group, anoptionally halo-substituted, straight, branched or cyclic, C₁-C₆ alkylgroup, or an optionally halo-substituted, straight, branched or cyclic,C₁-C₆ alkoxy group; D is a single bond or a straight, branched orcyclic, C₁-C₁₀ (v+1)-valent hydrocarbon group which may contain anethereal oxygen atom, carbonyl moiety or carbonyloxy moiety at anintermediate of the chain, in which some or all carbon-bonded hydrogenatoms may be substituted by fluorine; Rf¹ and Rf² are each independentlya C₁-C₆ alkyl group containing at least one fluorine atom, Rf' may bondwith D to form a ring with the carbon atoms to which they are attached;r is 0 or 1, h is an integer of 1 to 3, u is an integer of 0 to 2, c isequal to (5+2u−h), and v is 1 or 2.

Preferably the polymer further comprises recurring units of at least onetype selected from units having the formulae (4) and (5).

Herein R⁵ and R⁶ are each independently hydrogen, halogen, an optionallyhalo-substituted, straight, branched or cyclic, C₂-C₈ acyloxy group, anoptionally halo-substituted, straight, branched or cyclic, C₁-C₆ alkylgroup, or an optionally halo-substituted, straight, branched or cyclic,C₁-C₆ alkoxy group; i and j are each independently an integer of 0 to 2,d is equal to (6−i), and e is equal to (4−j).

Preferably the polymer further comprises recurring units of at least onetype selected from units having the formulae (A) to (E).

Herein R¹ is as defined above; X^(A) is an acid labile group; X^(B) andX^(c) are each independently a single bond or a straight or branchedC₁-C₄ divalent hydrocarbon group; X^(D) is a straight, branched orcyclic, C₁-C₁₆ di- to pentavalent aliphatic hydrocarbon group in whichany constituent —CH₂— may be substituted by —O— or —C(═O)—; X^(E) is anacid labile group; Y^(A) is a substituent group having a lactone,sultone or carbonate structure; Z^(A) is hydrogen, a C₁-C₃₀ fluoroalkylgroup or a C₁-C₁₅ fluoroalcohol-containing substituent group; k^(1A) isan integer of 1 to 3, and k^(1B) is an integer of 1 to 4.

Preferably the polymer further comprises recurring units having theformula (F).

Herein R¹⁰¹ is hydrogen or methyl; X is a single bond, —C(═O)—,—C(═O)—O— or —C(═O)—NH—; R¹⁰² is a single bond or a straight, branchedor cyclic C₁-C₁₀ alkylene group which may contain an ether, ester,carbonyl moiety, —N═ or —S—, or a phenylene or naphthylene group; R¹⁰³and R¹⁰⁴ are each independently hydrogen, a straight or branched C₁-C₄alkyl group, or an acid labile group, or R¹⁰³ and R¹⁰⁴ may bond togetherto form a ring with the nitrogen atom to which they are attached, thering optionally containing an ether bond, or either one of R¹⁰³ and R¹⁰⁴may bond with R¹⁰² to form a ring with the nitrogen atom to which theyare attached; and k^(1C) is 1 or 2.

The shrink material may further comprise a salt having the formula (9):

R¹¹—CO₂ ⁻  (9)

wherein R¹¹ is a straight, branched or cyclic C₁-C₂₀ alkyl group,straight, branched or cyclic C₂-C₂₀ alkenyl group or C₆-C₂₀ monovalentaromatic ring-containing group, in which some or all carbon-bondedhydrogen atoms may be substituted by fluorine, lactone ring-containingmoiety, lactam ring-containing moiety or hydroxyl moiety, and in whichan ether, ester or carbonyl moiety may intervene in a carbon-carbonbond, and M⁺ is a sulfonium, iodonium or ammonium cation.

The shrink material may further comprise a salt having the formula (10):

R¹²—SO₃ ⁻M⁺  (10)

wherein R¹² is a straight, branched or cyclic C₁-C₃₅ monovalenthydrocarbon group which may contain an oxygen atom, in which some or allcarbon-bonded hydrogen atoms may be substituted by fluorine, with theproviso that the hydrogen atom bonded to the carbon atom at α-positionrelative to sulfonic acid is not substituted by fluorine, and M⁺ is asulfonium, iodonium or ammonium cation.

In a preferred embodiment, the shrink material may further comprise atleast one basic compound selected from the group consisting of primary,secondary and tertiary aliphatic amines, mixed amines, aromatic amines,heterocyclic amines, nitrogen-containing compounds having carboxylgroup, nitrogen-containing compounds having sulfonyl group,nitrogen-containing compounds having hydroxyl group, nitrogen-containingcompounds having hydroxyphenyl group, alcoholic nitrogen-containingcompounds, amide derivatives, imide derivatives, and carbamates.

Preferably, the anti-vanishing solvent is an ester solvent of 7 to 16carbon atoms, ketone solvent of 8 to 16 carbon atoms, or alcohol solventof 4 to 10 carbon atoms.

Specifically, the anti-vanishing solvent is at least one solventselected from the group consisting of:

ester solvents of 7 to 16 carbon atoms including pentyl acetate,isopentyl acetate, 2-methylbutyl acetate, hexyl acetate, 2-ethylhexylacetate, cyclohexyl acetate, methylcyclohexyl acetate, hexyl formate,ethyl valerate, propyl valerate, isopropyl valerate, butyl valerate,isobutyl valerate, tert-butyl valerate, pentyl valerate, isopentylvalerate, ethyl isovalerate, propyl isovalerate, isopropyl isovalerate,butyl isovalerate, isobutyl isovalerate, tert-butyl isovalerate,isopentyl isovalerate, ethyl 2-methylvalerate, butyl 2-methylvalerate,ethyl pivalate, propyl pivalate, isopropyl pivalate, butyl pivalate,tert-butyl pivalate, ethyl pentenoate, propyl pentenoate, isopropylpentenoate, butyl pentenoate, tert-butyl pentenoate, propyl crotonate,isopropyl crotonate, butyl crotonate, tert-butyl crotonate, butylpropionate, isobutyl propionate, tert-butyl propionate, benzylpropionate, ethyl hexanoate, allyl hexanoate, propyl butyrate, butylbutyrate, isobutyl butyrate, 3-methylbutyl butyrate, tert-butylbutyrate, ethyl 2-methylbutyrate, isopropyl 2-methylbutyrate, methylbenzoate, ethyl benzoate, propyl benzoate, butyl benzoate, phenylacetate, benzyl acetate, methyl phenylacetate, benzyl formate,phenylethyl formate, methyl 3-phenylpropionate, ethyl phenylacetate, and2-phenylethyl acetate,

ketone solvents of 8 to 16 carbon atoms including 2-octanone,3-octanone, 4-octanone, 2-nonanone, 3-nonanone, 4-nonanone, 5-nonanone,diisobutyl ketone, ethylcyclohexanone, ethylacetophenone, ethyl n-butylketone, di-n-butyl ketone, and diisobutyl ketone, and

alcohol solvents of 4 to 10 carbon atoms including 1-butanol, 2-butanol,isobutyl alcohol, t-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol,t-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol,3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol,2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol,3,3-dimethyl-2-butanol, 2,2-diethyl-1-butanol, 2-methyl-1-pentanol,2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol,3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol,4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and 1-octanol.

Preferably the solvent contains the anti-vanishing solvent and anadditional solvent, and the additional solvent is selected from thegroup consisting of 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone,4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone,methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate,butyl acetate, isobutyl acetate, pentyl acetate, isopentyl acetate,butenyl acetate, propyl formate, butyl formate, isobutyl formate, pentylformate, isopentyl formate, methyl valerate, methyl pentenoate, methylcrotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyllactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethylbenzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzylformate, phenylethyl formate, methyl 3-phenylpropionate, benzylpropionate, ethyl phenylacetate, and 2-phenylethyl acetate.

In another aspect, the invention provides a pattern forming processcomprising the steps of applying a resist composition onto a substrate,the resist composition comprising a base resin comprising recurringunits having an acid labile group-substituted carboxyl group, an acidgenerator and an organic solvent, prebaking to form a resist film;exposing the resist film to high-energy radiation, baking the film;developing the exposed resist film in an organic solvent-based developerto form a negative resist pattern; applying the shrink material definedherein onto the negative resist pattern, baking; and removing theexcessive shrink material with an organic solvent.

Typically, the base resin in the resist composition comprises recurringunits (a) having an acid labile group-substituted carboxyl group,represented by the formula (11)

Herein R²¹ is hydrogen or methyl, R²² is an acid labile group, Z is asingle bond or —C(═O)—O—R²³—, and R²³ is a straight, branched or cyclicC₁-C₁₀ alkylene group in which an ether or ester bond may intervene in acarbon-carbon bond, or naphthylene group.

In the pattern forming process, the developer comprises at least oneorganic solvent selected from the group consisting of 2-octanone,2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone,3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone,methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate,pentyl acetate, isopentyl acetate, butenyl acetate, propyl formate,butyl formate, isobutyl formate, pentyl formate, isopentyl formate,methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate,methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyllactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate,pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate,benzyl acetate, methyl phenylacetate, benzyl formate, phenylethylformate, methyl 3-phenylpropionate, benzyl propionate, ethylphenylacetate, and 2-phenylethyl acetate.

Preferably, the step of removing the excessive shrink material uses atleast one organic solvent selected from the group consisting of propylacetate, butyl acetate, isobutyl acetate, butenyl acetate, pentylacetate, isopentyl acetate, 2-methylbutyl acetate, hexyl acetate,2-ethylhexyl acetate, cyclohexyl acetate, methylcyclohexyl acetate,propyl formate, butyl formate, isobutyl formate, pentyl formate,isopentyl formate, hexyl formate, methyl valerate, ethyl valerate,propyl valerate, isopropyl valerate, butyl valerate, isobutyl valerate,tert-butyl valerate, pentyl valerate, isopentyl valerate, ethylisovalerate, propyl isovalerate, isopropyl isovalerate, butylisovalerate, isobutyl isovalerate, tert-butyl isovalerate, isopentylisovalerate, ethyl 2-methylvalerate, butyl 2-methylvalerate, methylcrotonate, ethyl crotonate, propyl crotonate, isopropyl crotonate, butylcrotonate, tert-butyl crotonate, methyl propionate, ethyl propionate,ethyl pentenoate, propyl pentenoate, isopropyl pentenoate, butylpentenoate, tert-butyl pentenoate, methyl lactate, ethyl lactate, propyllactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyllactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, ethylpivalate, propyl pivalate, isopropyl pivalate, butyl pivalate,tert-butyl pivalate, butyl propionate, isobutyl propionate, tert-butylpropionate, benzyl propionate, ethyl 3-ethoxypropionate, ethylhexanoate, allyl hexanoate, propyl butyrate, butyl butyrate, isobutylbutyrate, 3-methylbutyl butyrate, tert-butyl butyrate, ethyl2-methylbutyrate, isopropyl 2-methylbutyrate, methyl benzoate, ethylbenzoate, propyl benzoate, butyl benzoate, phenyl acetate, benzylacetate, methyl phenylacetate, benzyl formate, phenylethyl formate,methyl 3-phenylpropionate, ethyl phenylacetate, 2-phenylethyl acetate,2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone,2-octanone, 3-octanone, 4-octanone, 2-nonanone, 3-nonanone, 4-nonanone,5-nonanone, methylcyclohexanone, ethylcyclohexanone, acetophenone,methylacetophenone, ethylacetophenone, ethyl n-butyl ketone, di-n-butylketone, diisobutyl ketone, 1-butanol, 2-butanol, isobutyl alcohol,t-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, t-pentyl alcohol,neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol,3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol,2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol,2,2-diethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol,2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol,3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol,4-methyl-3-pentanol, cyclohexanol, and 1-octanol.

Typically, the high-energy radiation is i-line of wavelength 364 nm, KrFexcimer laser of wavelength 248 nm, ArF excimer laser of wavelength 193nm, EUV of wavelength 13.5 nm, or EB.

Advantageous Effects of Invention

The process involving forming a resist film based on a base resin havingan acid labile group-substituted carboxyl group and an acid generator,subjecting it to exposure and organic solvent development to form anegative tone resist pattern, and applying the shrink material of theinvention to the resist pattern, is successful in shrinking the size ofholes and/or slits in the resist pattern in a controlled manner.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1(A) to FIG. 1(F) illustrates, in cross-sectional view, steps of apattern forming or shrinking process according to the invention; FIG.1(A) showing a resist film formed on a substrate; FIG. 1(B) showing theresist film during exposure; FIG. 1(C) showing pattern formation afterPEB and development of the resist film; FIG. 1(D) showing a shrinkmaterial coated on the resist pattern; FIG. 1(E) showing the resistpattern whose spaces have been shrunk by baking and removal of theexcessive shrink material; and FIG. 1(F) showing dry etching of thesubstrate through the shrunk pattern as a mask.

DESCRIPTION OF PREFERRED EMBODIMENTS

The terms “a” and “an” herein do not denote a limitation of quantity,but rather denote the presence of at least one of the referenced item.“Optional” or “optionally” means that the subsequently described eventor circumstances may or may not occur, and that description includesinstances where the event or circumstance occurs and instances where itdoes not. As used herein, the notation (C_(n)-C_(m)) means a groupcontaining from n to m carbon atoms per group. As used herein, the term“film” is used interchangeably with “coating” or “layer.”

The abbreviations and acronyms have the following meaning.

EB: electron beam

Mw: weight average molecular weight

Mn: number average molecular weight

Mw/Mn: molecular weight distribution or dispersity

GPC: gel permeation chromatography

PEB: post-exposure bake

PAG: photoacid generator

In chemical formulae, Me stands for methyl, Ac stands for acetyl; andthe broken line denotes a valence bond.

Shrink Material

The invention provides a shrink material comprising a polymer and asolvent containing an anti-vanishing solvent which does not cause aresist pattern after development to vanish. The polymer is defined ascomprising recurring units of at least one type selected from unitshaving the formulae (1a) and (1b). Note that this polymer is sometimesreferred to as “shrink material polymer”.

In formulae (1a) and (1b), “A” is a single bond or a C₁-C₁₀ alkylenegroup which may contain an ethereal oxygen atom at an intermediateposition of the chain. Suitable alkylene groups include methylene,ethylene, propylene, trimethylene, tetramethylene, pentamethylene,hexamethylene, cyclopentylene, cyclohexylene, and structural isomersthereof having branched or cyclic structure. Inter alia, A is preferablya single bond, methylene, ethylene, propylene or trimethylene. When A isa group containing an ethereal oxygen atom, in the case of m=1 informula (1), the ethereal oxygen atom may be included at any positionexcluding between the carbons at α and β-positions relative to the esteroxygen. In the case of m=0, the ethereal oxygen atom becomes the atombonding to the backbone while a second ethereal oxygen atom may beincluded at any position excluding between the carbons at α andβ-positions relative to the ethereal oxygen atom.

In formulae (1a) and (1b), R¹ is hydrogen, fluorine, methyl ortrifluoromethyl. R² is each independently hydrogen, halogen, anoptionally halo-substituted, straight, branched or cyclic, C₂-C₈ acyloxygroup, an optionally halo-substituted, straight, branched or cyclic,C₁-C₆ alkyl group, or an optionally halo-substituted, straight, branchedor cyclic, C₁-C₆ alkoxy group.

Exemplary of the halogen are fluorine, chlorine, bromine and iodine.Suitable acyloxy groups include acetoxy, propionyloxy, butyryloxy,pivaloyloxy, and cyclohexylcarbonyloxy. Suitable alkyl groups includemethyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, t-butyl, pentyl,cyclopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decanyl, undecyl,dodecyl, norbornyl and adamantyl. Suitable alkoxy groups includemethoxy, ethoxy, propoxy, isopropoxy, n-butoxy, s-butoxy, t-butoxy,pentyloxy, hexyloxy, cyclopentyloxy, cyclohexyloxy,1-methyl-1-cyclopentyloxy, 1-ethyl-1-cyclopentyloxy,1-methyl-1-cyclohexyloxy, and 1-ethyl-1-cyclohexyloxy.

In formulae (1a) and (1b), L is hydrogen, a straight, branched orcyclic, C₁-C₁₀ monovalent aliphatic hydrocarbon group which may containan ethereal oxygen atom, carbonyl moiety or carbonyloxy moiety at anintermediate position of the chain, or an optionally substituted,monovalent aromatic ring-containing group. Suitable monovalent aliphatichydrocarbon groups are straight, branched or cyclic alkyl, alkenyl andalkynyl groups. Suitable alkyl groups include the above-exemplifiedgroups, but having 1 to 10 carbon atoms. Suitable alkenyl groups includevinyl, allyl, propenyl, cyclopropenyl, butenyl, cyclobutenyl, pentenyl,cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl,methylcyclohexenyl, octenyl, dimethylcyclohexenyl, and cyclooctenyl.Suitable alkynyl groups include ethynyl, propynyl, butynyl, pentynyl,hexynyl, heptynyl, and octynyl. Suitable monovalent aromaticring-containing groups include phenyl, naphthyl, phenanthryl, anthryl,pyrenyl, biphenylyl, acenaphthenyl, and fluorenyl. Preferably, L ishydrogen, methyl, ethyl, propyl, isopropyl, cyclopentyl, cyclohexyl,adamantyl, methylcarbonyl, or phenyl.

In formula (1a), Z bonds with the carbon atom to form a C₅-C₁₅ alicyclicgroup. Suitable alicyclic groups include the following, but are notlimited thereto.

In formula (1b), R^(x) and R^(y) are each independently hydrogen or astraight, branched or cyclic, C₁-C₁₅ alkyl group which may besubstituted with a hydroxyl or alkoxy moiety, at least one of R^(x) andR^(y) being a cyclic C₅-C₁₅ alkyl group. Preferably, R^(x) and R^(y) areselected from methyl, ethyl, propyl, butyl, cyclopentyl, cyclohexyl,cycloheptyl, cyclooctyl, adamantyl, norbornyl, and the foregoing groupswhich are substituted with a hydroxyl or alkoxy moiety.

In formulae (1a) and (1b), f is an integer of 1 to 3, s is an integer of0 to 2, a is equal to (5+2s−f), and m is 0 or 1.

Among the recurring units of formulae (1a) and (1b), recurring units ofthe following formulae (1a′) and (1b′) are preferred.

Herein R¹, R^(x), R^(y), L and f are as defined above.

Preferred examples of the recurring units of formulae (1a) and (1b) areshown below, but not limited thereto.

Preferably, the shrink material polymer further comprises recurringunits of formula (2) and/or (3) in order to provide a sufficientattachment to the resist pattern and adhesion to the substrate. Therecurring unit of formula (2) or (3) permits an appropriate thermalvibration of the polymer that advantageously promotes insolubilizingreaction for the polymer to become insolubilized in the shrink materialstripper as a result of elimination of the acid labile group in therecurring unit of formula (1a) or (1b). In particular, recurring unitsof formula (2) are more preferred.

In formula (2), B is a single bond or a C₁-C₁₀ alkylene group which maycontain an ethereal oxygen atom at an intermediate position of thechain. Suitable alkylene groups are as exemplified above for “A”.

In formula (2), R¹ is as defined above. R³ is each independentlyhydrogen, halogen, an optionally halo-substituted, straight, branched orcyclic, C₂-C₈ acyloxy group, an optionally halo-substituted, straight,branched or cyclic, C₁-C₆ alkyl group, or an optionallyhalo-substituted, straight, branched or cyclic, C₁-C₆ alkoxy group.Examples of the acyloxy, alkyl and alkoxy groups are as exemplifiedabove for R². In formula (2), g is an integer of 0 to 3, t is an integerof 0 to 2, b is equal to (5+2t−g), and n is 0 or 1. Herein, g isindicative of the number of hydroxyl groups bonded to aromatic ring.Preferably g is at least 1 for the purpose of acquiring a sufficientamount of shrinkage by providing a high activity to insolubilizingreaction for the polymer to become insolubilized in the stripper as aresult of elimination of the acid labile group in the recurring unit offormula (1a) or (1b). More preferably, those units of formula (2)wherein g is at least 1 account for at least 50 mol % of the units offormula (2). The unit of formula (2) wherein g=0 may not be includeddepending on a particular design, although it is effective foradjustment of dissolution rate and adjustment of permission of thermalvibration of the polymer.

Of the recurring units of formula (2), linker-free recurring units, thatis, those recurring units of formula (2) wherein g is at least 1, n=0,and B is a single bond, that is, the aromatic ring is directly bonded tothe polymer backbone are units derived from monomers having a1-substituted or unsubstituted vinyl group attached to ahydroxy-substituted aromatic ring, typically hydroxystyrene units.Suitable units include those derived from 3-hydroxystyrene,4-hydroxystyrene, 5-hydroxy-2-vinyl-naphthalene, and6-hydroxy-2-vinylnaphthalene. Preferred are those units derived from3-hydroxystyrene or 4-hydroxystyrene, as represented by the followingformula (2′).

Herein R′ is as defined above and k is an integer of 1 to 3.

Of the recurring units of formula (2), linker-bearing recurring units,that is, those recurring units of formula (2) wherein n=1, that is,having an ester structure linker are units derived fromcarbonyl-substituted vinyl monomers, typically (meth)acrylates.

Of the recurring units of formula (2) having a linker (—CO—O—B—) derivedfrom (meth)acrylate, preferred examples of those units wherein g is atleast 1 are shown below, but not limited thereto.

Of the recurring units of formula (2), those units wherein g=0 are unitsderived from styrene, vinylnaphthalene, vinylanthracene and theforegoing compounds whose aromatic ring is substituted with halogen,acyloxy, alkyl, alkoxy or similar moiety. Those units wherein g=0 andhaving a linker (—CO—O—B—) derived from (meth)acrylate include thepreferred examples of the unit wherein g is at least 1, from which thehydroxyl group is eliminated, and in which the hydrogen of the hydroxylgroup is substituted by an acyl or alkyl group.

In formula (3), C is a single bond or a C₁-C₁₀ alkylene group which maycontain an ethereal oxygen atom at an intermediate position of thechain. Suitable alkylene groups are as exemplified above for “A”.

In formula (3), R¹ is as defined above. R⁴ is each independentlyhydrogen, halogen, an optionally halo-substituted, straight, branched orcyclic, C₂-C₈ acyloxy group, an optionally halo-substituted, straight,branched or cyclic, C₁-C₆ alkyl group, or an optionallyhalo-substituted, straight, branched or cyclic, C₁-C₆ alkoxy group.Examples of the acyloxy, alkyl and alkoxy groups are as exemplifiedabove for R².

In formula (3), D is a single bond or a straight, branched or cyclic,C₁-C₁₀ (v+1)-valent hydrocarbon group which may contain an etherealoxygen atom, carbonyl moiety or carbonyloxy moiety at an intermediateposition of the chain, in which some or all carbon-bonded hydrogen atomsmay be substituted by fluorine. The preferred hydrocarbon groups arealiphatic hydrocarbon groups, examples of which are the same groups asexemplified above for the monovalent aliphatic hydrocarbon group of L,with a number “v” of hydrogen atoms being eliminated.

In formula (3), Rf¹ and Rf² are each independently a C₁-C₆ alkyl groupcontaining at least one fluorine atom. Rf¹ may bond with D to form aring with the carbon atoms to which they are attached. Suitable alkylgroups containing at least one fluorine atom include monofluoromethyl,difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl,1,1,2,2,2-pentafluoroethyl, 2,2,2-trifluoro-1-(trifluoromethyl)ethyl,perfluoroisopropyl, heptafluoropropyl, 2,2,3,3-tetrafluoropropyl,2,2,3,3,3-pentafluoropropyl, 3,3,3-trifluoro-2-(trifluoromethyl)propyl,nonafluorobutyl, 1H,1H,5H-octafluoropentyl, 1H,1H-nonafluoropentyl,perfluoropentyl, 1H,1H-4-trifluoromethylperfluoropentyl, perfluorohexyl,4-pentafluoroethylperfluorocyclohexyl, 1H,1H,2H,2H-perfluorohexyl, andperfluorocyclohexyl.

In formula (3), h is an integer of 1 to 3, u is an integer of 0 to 2,and c is equal to (5+2u−h).

In formula (3), r is 0 or 1. In the case of r=1, an aromatic ringintervenes between the polymer backbone and the hydroxyl group bonded tothe carbon vicinal to the carbon substituted with a fluorine-containinggroup. In this case, v indicative of the number of substituents on D is1 or 2. If D is not a single bond, D has one or two hydroxyl groups eachbonded to the carbon vicinal to the carbon substituted with afluorine-containing group, that is, v is 1 or 2.

In the case of r=0, h is 1, and C is a single bond, but

D is not a single bond. In this case, D bonds with the polymer backbonevia the carbonyloxy group. In this case too, D has one or two hydroxylgroups each bonded to the carbon vicinal to the carbon substituted witha fluorine-containing group.

Preferred examples of the recurring unit having formula (3) are shownbelow, but not limited thereto.

The units of formula (2) or (3) may be used alone or in admixture (i.e.,of one type or two or more types).

The shrink material polymer may further comprise recurring units of atleast one type selected from units having the following formulae (4) and(5) as main constituent units. In this embodiment, the polymer may haveanother advantage that the binding of cyclic structure to the backboneimparts dry etching resistance to the shrunk resist pattern, in additionto the advantage of etch resistance inherent to aromatic ring.

Herein R⁵ and R⁶ are each independently hydrogen, halogen, an optionallyhalo-substituted, straight, branched or cyclic, C₂-C₈ acyloxy group, anoptionally halo-substituted, straight, branched or cyclic, C₁-C₆ alkylgroup, or an optionally halo-substituted, straight, branched or cyclic,C₁-C₆ alkoxy group. Examples of the acyloxy, alkyl and alkoxy groups areas exemplified above for R².

In formulae (4) and (5), i and j are each independently an integer of 0to 2, d is equal to (6−i), and e is equal to (4−j).

The units of formula (4) or (5) may be used alone or in admixture (i.e.,of one type or two or more types).

Where the unit of formula (4) or (5) wherein i or j is at least 1 isselected, in relation to other recurring units of the polymer, for thepurpose of enhancing the etch resistance of the polymer, the compoundsfrom which the following units (4′) or (5′) are derived are readilyavailable and effective for achieving the desired effects.

The shrink material polymer may further comprise recurring units of atleast one type selected from units having the following formulae (A) to(E). These units may be used as auxiliary units capable of making thepolymer more adhesive to the resist pattern or for adjusting thesolubility of the polymer in solvents.

Herein R¹ is as defined above. X^(A) is an acid labile group. X^(B) andX^(C) are each independently a single bond or a straight or branchedC₁-C₄ divalent hydrocarbon group. X^(D) is a straight, branched orcyclic, C₁-C₁₆ di- to pentavalent aliphatic hydrocarbon group in whichany constituent —CH₂— may be substituted by —O— or —C(═O)—. X^(E) is anacid labile group. Y^(A) is a substituent group having a lactone,sultone or carbonate structure. Z^(A) is hydrogen, a C₁-C₃₀ fluoroalkylgroup or a C₁-C₁₅ fluoroalcohol-containing substituent group, k^(1A) isan integer of 1 to 3, and k^(1B) is an integer of 1 to 4.

The recurring unit of formula (A) is decomposed under the action of acidto generate carboxylic acid. By incorporating this unit, the solubilityof the shrink material polymer in organic solvent may be adjusted. Theacid labile group represented by X^(A) may be selected from a variety ofsuch groups. Examples of the acid labile group include groups of thefollowing general formulae (L1) to (L4), tertiary alkyl groups of 4 to20 carbon atoms, preferably 4 to 15 carbon atoms, trialkylsilyl groupsin which each alkyl moiety has 1 to 6 carbon atoms, and oxoalkyl groupsof 4 to 20 carbon atoms.

Herein R^(L01) and R^(L02) are each independently hydrogen or astraight, branched or cyclic alkyl group of 1 to 18 carbon atoms,preferably 1 to 10 carbon atoms. R^(L03) is a monovalent hydrocarbongroup of 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, whichmay contain a heteroatom such as oxygen, examples of which includestraight, branched or cyclic alkyl groups, substituted forms of suchalkyl groups in which some hydrogen atoms are replaced by hydroxyl,alkoxy, oxo, amino, alkylamino or the like, and similar groups which areseparated by an ethereal oxygen atom. R^(L04) is a tertiary alkyl groupof 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, atrialkylsilyl group in which each alkyl moiety has 1 to 6 carbon atoms,an oxoalkyl group of 4 to 20 carbon atoms, or a group of formula (L1).R^(L05) is an optionally substituted, straight, branched or cyclicC₁-C₁₀ alkyl group or an optionally substituted C₆-C₂₀ aryl group.R^(L06) is an optionally substituted, straight, branched or cyclicC₁-C₁₀ alkyl group or an optionally substituted C₆-C₂₀ aryl group.R^(L07) to R^(L16) independently represent hydrogen or optionallysubstituted monovalent hydrocarbon groups of 1 to 15 carbon atoms.Letter x is an integer of 0 to 6, y is equal to 0 or 1, z is equal to 0,1, 2 or 3, and 2y+z is equal to 2 or 3.

In formula (L1), exemplary groups of R^(L01) and R^(L02) include methyl,ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, cyclopentyl,cyclohexyl, 2-ethylhexyl, n-octyl, and adamantyl.

Examples of the monovalent hydrocarbon group represented by R^(L03) areas exemplified above for the alkyl group represented by R^(L01) andR^(L02), but not limited thereto. Examples of the substituted alkylgroup represented by R^(L03) are as shown below.

Apair of R^(L01) and R^(L02), R^(L01) and R^(L03), or R^(L02) andR^(L03) may bond together to form a ring with the carbon and oxygenatoms to which they are attached. Each of ring-forming R^(L01), R^(L02)and R^(L03) is a straight or branched alkylene group of 1 to 18 carbonatoms, preferably 1 to 10 carbon atoms when they form a ring.

In formula (L2), exemplary tertiary alkyl groups of R^(L04) aretert-butyl, tert-pentyl, 1,1-diethylpropyl, 2-cyclopentylpropan-2-yl,2-cyclohexylpropan-2-yl, 2-(bicyclo[2.2.1]heptan-2-yl)propan-2-yl,2-(adamantan-1-yl)propan-2-yl, 1-ethylcyclopentyl, 1-butylcyclopentyl,1-ethylcyclohexyl, 1-butylcyclohexyl, 1-ethyl-2-cyclopentenyl,1-ethyl-2-cyclohexenyl, 2-methyl-2-adamantyl, and 2-ethyl-2-adamantyl.Exemplary trialkylsilyl groups are trimethylsilyl, triethylsilyl, anddimethyl-tert-butylsilyl. Exemplary oxoalkyl groups are 3-oxocyclohexyl,4-methyl-2-oxooxan-4-yl, and 5-methyl-2-oxooxolan-5-yl.

In formula (L3), examples of the alkyl groups of R^(L05) includestraight, branched or cyclic alkyl groups such as methyl, ethyl, propyl,isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl,n-hexyl, cyclopentyl, cyclohexyl, and bicyclo[2.2.1]heptyl, andsubstituted forms of such groups in which some hydrogen atoms arereplaced by hydroxyl, alkoxy, carboxyl, alkoxycarbonyl, oxo, amino,alkylamino, cyano, mercapto, alkylthio, sulfo or the like or in which amethylene moiety is replaced by an oxygen or sulfur atom. Examples ofthe aryl groups of R^(L05) include phenyl, methylphenyl, naphthyl,anthryl, phenanthryl, and pyrenyl.

In formula (L4), examples of the alkyl and aryl groups of R^(L06) arethe same as exemplified for R^(L05). Exemplary C₁-C₁₅ monovalenthydrocarbon groups of R^(L07) to R^(L16) include straight, branched orcyclic alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl,sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, n-nonyl,n-decyl, cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl,cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl and cyclohexylbutyl,and substituted forms of these groups in which some hydrogen atoms arereplaced by hydroxyl, alkoxy, carboxyl, alkoxycarbonyl, oxo, amino,alkylamino, cyano, mercapto, alkylthio, sulfo or the like.Alternatively, two of R^(L07) to R^(L16) may bond together to form aring with the carbon atom(s) to which they are attached (for example, apair of R^(L07) and R^(L08), R^(L07) and R^(L09), R^(L08) and R^(L10),R^(L09) and R^(L10), R^(L11) and R^(L12), or R^(L13) and R^(L14) form aring). Each of R^(L07) to R^(L16) represents a C₁-C₁₅ divalenthydrocarbon group, typically alkylene, when they form a ring, examplesof which are those exemplified above for the monovalent hydrocarbongroups, with one hydrogen atom being eliminated. Two of R^(L07) toR^(L16) which are attached to vicinal carbon atoms may bond togetherdirectly to form a double bond (for example, a pair of R^(L07) andR^(L09), R^(L09) and R^(L15), or R^(L13) and R^(L15)).

Of the acid labile groups of formula (L1), the straight and branchedones are exemplified by the following groups, but not limited thereto.

Of the acid labile groups of formula (L1), the cyclic ones are, forexample, tetrahydrofuran-2-yl, 2-methyltetrahydrofuran-2-yl,tetrahydropyran-2-yl, and 2-methyltetrahydropyran-2-yl.

Examples of the acid labile groups of formula (L2) includetert-butoxycarbonyl, tert-butoxycarbonylmethyl, tert-pentyloxycarbonyl,tert-pentyloxycarbonylmethyl, 1,1-diethylpropyloxycarbonyl,1,1-diethylpropyloxycarbonylmethyl, 1-ethyl cyclopentyloxycarbonyl,1-ethyl cyclopentyloxycarbonylmethyl,1-ethyl-2-cyclopentenyloxycarbonyl,1-ethyl-2-cyclopentenyloxycarbonylmethyl, 1-ethoxyethoxycarbonylmethyl,2-tetrahydropyranyloxycarbonylmethyl, and2-tetrahydrofuranyloxycarbonylmethyl.

Examples of the acid labile groups of formula (L3) include1-methylcyclopentyl, 1-ethylcyclopentyl, 1-n-propylcyclopentyl,1-isopropylcyclopentyl, 1-n-butylcyclopentyl, 1-sec-butylcyclopentyl,1-cyclohexylcyclopentyl, 1-(4-methoxy-n-butyl)cyclopentyl,1-(bicyclo[2.2.1]heptan-2-yl)cyclopentyl,1-(7-oxabicyclo[2.2.1]heptan-2-yl)cyclopentyl, 1-methylcyclohexyl,1-ethylcyclohexyl, 3-methyl-1-cyclopenten-3-yl,3-ethyl-1-cyclopenten-3-yl, 3-methyl-1-cyclohexen-3-yl, and3-ethyl-1-cyclohexen-3-yl.

Of the acid labile groups of formula (L4), those groups of the followingformulae (L4-1) to (L4-4) are preferred.

In formulas (L4-1) to (L4-4), the broken line denotes a bonding site anddirection. R^(L41) is each independently a monovalent hydrocarbon group,typically a straight, branched or cyclic C₁-C₁₀ alkyl group, such asmethyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl,n-pentyl, tert-pentyl, n-hexyl, cyclopentyl and cyclohexyl.

For formulas (L4-1) to (L4-4), there can exist enantiomers anddiastereomers. Each of formulae (L4-1) to (L4-4) collectively representsall such stereoisomers. Where X^(A) is an acid labile group of formula(L4), a plurality of stereoisomers may be included.

For example, the formula (L4-3) represents one or a mixture of twoselected from groups having the following formulae (L4-3-1) and(L4-3-2).

Note that R^(L41) is as defined above.

Similarly, the formula (L4-4) represents one or a mixture of two or moreselected from groups having the following formulae (L4-4-1) to (L4-4-4).

Note that R^(L41) is as defined above.

Each of formulae (L4-1) to (L4-4), (L4-3-1) and (L4-3-2), and (L4-4-1)to (L4-4-4) collectively represents an enantiomer thereof and a mixtureof enantiomers.

It is noted that in the above formulas (L4-1) to (L4-4), (L4-3-1) and(L4-3-2), and (L4-4-1) to (L4-4-4), the bond direction is on the exoside relative to the bicyclo[2.2.1]heptane ring, which ensures highreactivity for acid catalyzed elimination reaction (see JP-A2000-336121). In preparing these monomers having a tertiary exo-alkylgroup of bicyclo[2.2.1]heptane structure as a substituent group, theremay be contained monomers substituted with an endo-alkyl group asrepresented by the following formulas (L4-1-endo) to (L4-4-endo). Forgood reactivity, an exo proportion of at least 50 mol % is preferred,with an exo proportion of at least 80 mol % being more preferred.

Note that R^(L41) is as defined above.

Illustrative examples of the acid labile group of formula (L4) are givenbelow.

Examples of the tertiary C₄-C₂₀ alkyl groups, trialkylsilyl groups inwhich each alkyl moiety has 1 to 6 carbon atoms, and C₄-C₂₀ oxoalkylgroups, represented by X^(A) are as exemplified for R^(L04).

Illustrative examples of the recurring units having formula (A) aregiven below, but not limited thereto. Herein R¹ is as defined above.

Illustrative examples of the recurring units having formula (B) aregiven below, but not limited thereto. Herein R¹ is as defined above.

Illustrative examples of the recurring units having formula (C) aregiven below, but not limited thereto. Herein R¹ is as defined above.

Illustrative examples of the recurring units having formula (D) aregiven below, but not limited thereto. Herein R¹ is as defined above.

A polymer comprising recurring units of formula (E) is decomposed underthe action of acid to generate a hydroxyl group so that its solubilityin various solvents may change. In formula (E), the acid labile groupX^(E) may be selected from a variety of such groups. Examples of theacid labile group X^(E) are groups of formulae (L1) to (L4), tertiaryalkyl groups of 4 to 20 carbon atoms, trialkylsilyl groups in which eachalkyl moiety has 1 to 6 carbon atoms, and oxoalkyl groups of 4 to 20carbon atoms, like the acid labile group X^(A) mentioned above.

Illustrative examples of the recurring units having formula (E) aregiven below, but not limited thereto. Herein R¹ is as defined above.

Of the recurring units of formulae (A) to (E), those units of formulae(A) to (C) are preferred in that the polymer may be readily adjustedthereby in solvent solubility and adhesion.

The shrink material polymer may further comprise recurring units of thefollowing formula (F). The unit of formula (F) may induce neutralizingreaction with the carboxyl group available on the surface of the resistpattern film to which the shrink material is applied. As a result, theshrink material polymer adheres to the resist film surface, indicatingan increased attachment.

Herein R¹⁰¹ is hydrogen or methyl. X is a single bond, —C(═O)—,—C(═O)—O— or —C(═O)—NH—. R¹⁰² is a single bond or a straight, branchedor cyclic C₁-C₁₀ alkylene group which may contain an ether, ester,carbonyl moiety, —N═ or —S—, or a phenylene or naphthylene group. R¹⁰³and R¹⁰⁴ are each independently hydrogen, a straight or branched C₁-C₄alkyl group, or an acid labile group, or R¹⁰³ and R¹⁰⁴ may bond togetherto form a ring with the nitrogen atom to which they are attached, thering optionally containing an ether bond, or either one of R¹⁰³ and R¹⁰⁴may bond with R¹⁰² to form a ring with the nitrogen atom to which theyare attached, and k^(1C) is 1 or 2.

The recurring unit of formula (F) may be derived from a monomer havingthe following formula (Fa).

Herein R¹⁰¹ to R¹⁰⁴, X and k^(1C) are as defined above.

Examples of the monomer having formula (Fa) are shown below, but notlimited thereto.

Herein R¹⁰¹ to R¹⁰⁴ are as defined above.

The shrink material polymers may be used alone or in admixture. When thepolymer is used alone, it is designed by selecting recurring unitshaving desired functions, and determining a constitutional ratio of therecurring units so as to provide an appropriate shrinkage anddimensional uniformity to the shrink material formulated therefrom.

The shrink material polymer may be prepared by combining suitablemonomers and copolymerizing them in the standard way while protectionand deprotection reactions are combined if necessary. Thecopolymerization reaction is preferably radical polymerization thoughnot limited thereto.

In the shrink material polymer, the recurring units of formula (1a)and/or (1b) are preferably incorporated in an amount of at least 5 mol%, more preferably at least 10 mol % based on the entire recurringunits.

The recurring units of formula (2) are preferably incorporated in anamount of 0 to 90 mol % based on the entire recurring units. For moreattachment to the resist pattern and substrate adhesion, the amount ofunits of formula (2) is more preferably 5 to 85 mol %, even morepreferably 10 to 80 mol %.

The recurring units of formula (3) are preferably incorporated in anamount of 0 to 90 mol % based on the entire recurring units. For moreattachment to the resist pattern and substrate adhesion, the amount ofunits of formula (3) is more preferably 5 to 85 mol %, even morepreferably 10 to 80 mol %.

The recurring units of formula (4) or (5) are preferably incorporated inan amount of 0 to 30 mol % based on the entire recurring units. For moreetch resistance, the amount of units of formula (4) or (5) is morepreferably 5 to 30 mol %, even more preferably 5 to 20 mol %.

The recurring units of formulae (A) to (E) are preferably incorporatedin an amount of 0 to 30 mol % based on the entire recurring units. Formore substrate adhesion and solubility adjustment, the amount of unitsof formulae (A) to (E) is more preferably 1 to 30 mol %, even morepreferably 5 to 20 mol %.

The recurring units of formula (F) are preferably incorporated in anamount of 0 to 30 mol % based on the entire recurring units. For moreattachment, the amount of units of formula (F) is more preferably 1 to30 mol %, even more preferably 1 to 20 mol %.

In the shrink material polymer, the recurring units of formula (1a)and/or (1b) and the recurring units selected from the units of formulae(2), (4) and (5) preferably account for at least 60 mol % based on theentire recurring units because this ensures to formulate a shrinkmaterial having the desired properties. More preferably the recurringunits of formula (1a) and/or (1b) and the recurring units of formulae(2), (4) and (5) account for at least 70 mol %, even more preferably atleast 85 mol % based on the entire recurring units.

When the entire constituent units of the shrink material polymer are therecurring units of formula (1a) and/or (1b) and the recurring unitsselected from the units of formulae (2), (4) and (5), high etchresistance and high resolution are available in a compatible manner. Inthe shrink material polymer, recurring units other than the recurringunits of formulae (1a), (1b), (2), (4) and (5) may be incorporated. Forexample, (meth)acrylate units protected with a conventional acid labilegroup and/or (meth)acrylate units having an adhesive group such aslactone structure may be used. Characteristics of a shrink material filmmay be finely adjusted by incorporating such additional recurring unitsalthough the additional recurring units are optional.

The shrink material polymer preferably has a weight average molecularweight (Mw) of 1,000 to 500,000, more preferably 2,000 to 100,000, andeven more preferably 2,000 to 20,000, as measured versus polystyrenestandards by GPC using tetrahydrofuran solvent. If Mw is too low, theacid diffusion distance may be extended and the shrinkage may beincreased and become uncontrollable. If Mw is too high, the solubilityin stripper solvent may be reduced to such an extent as to leave scum inspaces at the end of stripping step, resulting in a footing phenomenon.

If a polymer has a wide molecular weight distribution or dispersity(Mw/Mn), which indicates the presence of lower and higher molecularweight polymer fractions, there is a possibility that foreign matter isleft on the pattern or the pattern profile is degraded. The influencesof molecular weight and dispersity become stronger as the pattern rulebecomes finer. Therefore, the multi-component copolymer, i.e., shrinkmaterial polymer should preferably have a narrow dispersity (Mw/Mn) of1.0 to 2.0, especially 1.0 to 1.5, in order to provide a shrink materialsuitable for micropatterning to a small feature size.

It is acceptable to use a blend of two or more polymers which aredifferent in compositional ratio, molecular weight or dispersity.

In addition to the polymer defined above, the shrink material comprisesa solvent containing an anti-vanishing solvent which does not cause theresist pattern after development to vanish. Included in theanti-vanishing solvent are ether solvents of 6 to 12 carbon atoms,hydrocarbon solvents of 6 to 12 carbon atoms, ester solvents of 7 to 16carbon atoms, ketone solvents of 8 to 16 carbon atoms, alcohol solventsof 4 to 10 carbon atoms, and water. As long as the anti-vanishingsolvent accounts for at least 50% by weight of the overall solvent,another solvent that allows the resist pattern after development tovanish may be contained.

Although a number of water-based shrink materials are already proposed,they are difficult to quickly apply to large-diameter wafers because ofthe high surface tension of water. A problem arises particularly in thecase of a fine hole pattern formed via negative development. When holesare filled with the shrink material by spin coating, the water solventhaving a high surface tension prevents the shrink material from buryingin the holes to the bottom. In contrast, when a shrink materialdissolved in an organic solvent having a lower surface tension thanwater is applied, the ability to fill or bury to the hole bottom isimproved. Also the organic solvent used in the shrink material mustdissolve the shrink material polymer.

As the solvent used in the shrink material, ester solvents of 7 to 16carbon atoms, ketone solvents of 8 to 16 carbon atoms, and alcoholsolvents of 4 to 10 carbon atoms are preferred because of their highdissolving power to the shrink material polymer.

Examples of the ester solvents of 7 to 16 carbon atoms include pentylacetate, isopentyl acetate, 2-methylbutyl acetate, hexyl acetate,2-ethylhexyl acetate, cyclohexyl acetate, methylcyclohexyl acetate,hexyl formate, ethyl valerate, propyl valerate, isopropyl valerate,butyl valerate, isobutyl valerate, tert-butyl valerate, pentyl valerate,isopentyl valerate, ethyl isovalerate, propyl isovalerate, isopropylisovalerate, butyl isovalerate, isobutyl isovalerate, tert-butylisovalerate, isopentyl isovalerate, ethyl 2-methylvalerate, butyl2-methylvalerate, ethyl pivalate, propyl pivalate, isopropyl pivalate,butyl pivalate, tert-butyl pivalate, ethyl pentenoate, propylpentenoate, isopropyl pentenoate, butyl pentenoate, tert-butylpentenoate, propyl crotonate, isopropyl crotonate, butyl crotonate,tert-butyl crotonate, butyl propionate, isobutyl propionate, tert-butylpropionate, benzyl propionate, ethyl hexanoate, allyl hexanoate, propylbutyrate, butyl butyrate, isobutyl butyrate, 3-methylbutyl butyrate,tert-butyl butyrate, ethyl 2-methylbutyrate, isopropyl 2-methylbutyrate,methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, phenylacetate, benzyl acetate, methyl phenylacetate, benzyl formate,phenylethyl formate, methyl 3-phenylpropionate, ethyl phenylacetate, and2-phenylethyl acetate,

Examples of the ketone solvents of 8 to 16 carbon atoms include2-octanone, 3-octanone, 4-octanone, 2-nonanone, 3-nonanone, 4-nonanone,5-nonanone, diisobutyl ketone, ethylcyclohexanone, ethylacetophenone,ethyl n-butyl ketone, di-n-butyl ketone, and diisobutyl ketone.

Examples of the alcohol solvents of 4 to 10 carbon atoms include1-butanol, 2-butanol, isobutyl alcohol, t-butyl alcohol, 1-pentanol,2-pentanol, 3-pentanol, t-pentyl alcohol, neopentyl alcohol,2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol,cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol,3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2,2-diethyl-1-butanol,2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol,3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol,4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol,cyclohexanol, and 1-octanol. These solvents may be used alone or inadmixture.

For the purpose of preventing intermixing of the shrink material and theresist pattern, any of C₈-C₁₂ ether, C₆-C₁₂ alkane, alkene, alkyne andaromatic solvents may be blended with the anti-vanishing solvent.

Suitable ether compounds of 8 to 12 carbon atoms include di-n-butylether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether,diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, anddi-n-hexyl ether. Suitable alkanes of 6 to 12 carbon atoms includehexane, heptane, octane, nonane, decane, undecane, dodecane,methylcyclopentane, dimethylcyclopentane, cyclohexane,methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, andcyclononane. Suitable alkenes of 6 to 12 carbon atoms include hexene,heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene,cycloheptene, and cyclooctene. Suitable alkynes of 6 to 12 carbon atomsinclude hexyne, heptyne, and octyne. Suitable aromatic solvents includetoluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene,mesitylene, and anisole. The solvents may be used alone or in admixture.

In addition to the anti-vanishing solvent, the shrink material maycontain an additional solvent. The additional solvent is selected fromamong 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone,2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone,acetophenone, methylacetophenone, propyl acetate, butyl acetate,isobutyl acetate, pentyl acetate, isopentyl acetate, butenyl acetate,propyl formate, butyl formate, isobutyl formate, pentyl formate,isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate,ethyl crotonate, methyl propionate, ethyl propionate, ethyl3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyllactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethylbenzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzylformate, phenylethyl formate, methyl 3-phenylpropionate, benzylpropionate, ethyl phenylacetate, and 2-phenylethyl acetate. Theadditional solvent, if used, is preferably blended in an amount of lessthan 50% by weight of the overall solvent.

In the shrink material, the solvent is preferably used in an amount of100 to 100,000 parts, more preferably 200 to 50,000 parts by weight per100 parts by weight of the polymer.

To the shrink material, a salt, basic compound and surfactant may beadded if desired. The salt that can be added is typically selected fromsulfonium salts and iodonium salts which are typically added to resistcompositions, and ammonium salts. The basic compound that can be addedmay be selected from those basic compounds which are typically added toresist compositions, for example, primary, secondary and tertiaryaliphatic amines, mixed amines, aromatic amines, heterocyclic amines,nitrogen-containing compounds having carboxyl group, nitrogen-containingcompounds having sulfonyl group, nitrogen-containing compounds havinghydroxyl group, nitrogen-containing compounds having hydroxyphenylgroup, alcoholic nitrogen-containing compounds, amide derivatives, imidederivatives, and carbamates. The addition of the salt or basic compoundis effective for suppressing excessive diffusion of acid from within theresist film and for controlling the amount of shrinkage. The surfactantthat can be added may be selected from those surfactants which aretypically added to resist compositions.

As the salt, a carboxylic acid salt having the formula (9) is preferred.

R¹¹—CO₂ ⁻M⁺  (9)

Herein R¹¹ is a straight, branched or cyclic C₁-C₂₀ alkyl group,straight, branched or cyclic C₂-C₂₀ alkenyl group or C₆-C₂₀ monovalentaromatic ring-containing group, in which some or all carbon-bondedhydrogen atoms may be substituted by fluorine, lactone ring-containingmoiety, lactam ring-containing moiety or hydroxyl moiety, and in whichan ether, ester or carbonyl moiety may intervene in a carbon-carbonbond. M⁺ is a sulfonium, iodonium or ammonium cation.

Examples of the alkyl group, alkenyl group and monovalent aromaticring-containing group are as previously described.

The preferred sulfonium, iodonium and ammonium cations have thefollowing formulae (P1) to (P3). By adding a carboxylic acid salt havingsuch a cation, the acid diffusion can be effectively controlled.

Herein R¹⁰¹ to R¹⁰⁹ are each independently a straight, branched orcyclic C₁-C₁₂ alkyl or oxoalkyl group, a straight, branched or cyclicC₂-C₁₂ alkenyl or oxoalkenyl group, a C₆-C₂₀ monovalent aromaticring-containing group, or a C₇-C₁₂ aralkyl or aryloxoalkyl group, inwhich some or all hydrogen atoms may be substituted by halogen, alkyl,alkoxy or the like. A pair of R¹⁰¹ and R¹⁰², or R¹⁰⁶ and R¹⁰⁷ may bondtogether to form a ring with the sulfur or nitrogen atom to which theyare attached. When they form a ring, they together form a C₁-C₁₀alkylene or arylene group and the ring may contain an ether, ester,sultone or amino moiety therein.

Examples of the alkyl group, alkenyl group and monovalent aromaticring-containing group are as previously described. Suitable oxoalkyl andoxoalkenyl groups include the aforementioned alkyl and alkenyl groups inwhich an oxo moiety is bonded to a carbon atom. Suitable aralkyl groupsinclude benzyl, 1-phenylethyl, and 2-phenylethyl. Suitable aryloxoalkylgroups are 2-aryl-2-oxoethyl groups including 2-phenyl-2-oxoethyl,2-(1-naphthyl)-2-oxoethyl, and 2-(2-naphthyl)-2-oxoethyl.

Preferred examples of the anion of the foregoing carboxylic acid saltinclude the carboxylic acid anions described in JP 3991462, and thoseshown below, but are not limited thereto.

Preferred examples of the cation of the foregoing carboxylic acid saltinclude those shown below, but are not limited thereto.

A sulfonic acid salt having the formula (10) is also preferred as thesalt.

R¹²—SO₃ ⁻M⁺  (10)

Herein M⁺ is as defined above. R¹² is a straight, branched or cyclicC₁-C₃₅ monovalent hydrocarbon group which may contain an oxygen atom, inwhich some or all carbon-bonded hydrogen atoms may be substituted byfluorine, with the proviso that the hydrogen atom bonded to the carbonatom at a-position relative to sulfonic acid is not substituted byfluorine.

Of the sulfonic acid salts having formula (10), those having the formula(10′) are preferred.

Herein M is as defined above, R¹¹⁰ and R¹¹¹ are each independentlyhydrogen or trifluoromethyl, and 1 is an integer of 1 to 3.

In the shrink material, the salt is preferably used in an amount of 0 to50 parts, more preferably 0.1 to 20 parts by weight per 100 parts byweight of the polymer.

Exemplary basic compounds include primary, secondary and tertiary aminecompounds, specifically amine compounds having a hydroxyl, ether, ester,lactone, cyano or sulfonate group, as described in JP-A 2008-111103,paragraphs [0146] to [0164] (U.S. Pat. No. 7,537,880), and compoundshaving a carbamate group, as described in JP 3790649. Inter alia,tertiary amine compounds, specifically amine compounds having ahydroxyl, ether, ester group or lactone ring, and compounds having acarbamate group are preferred.

In the shrink material, the basic compound is preferably used in anamount of 0 to 30 parts, more preferably 0.1 to 20 parts by weight per100 parts by weight of the polymer.

Suitable surfactants include those described in JP-A 2008-111103,paragraphs [0165] to [0166]. The surfactant is preferably used in anamount of 0 to 10 parts, more preferably 0.1 to 5 parts by weight per100 parts by weight of the shrink material polymer.

Resist Composition

The resist composition used in the pattern forming process of theinvention is defined as comprising a base resin, an acid generator (orcompound capable of generating an acid in response to high-energyradiation) and an organic solvent. Optionally, the resist compositionfurther comprises a basic compound, dissolution regulator, surfactant,acetylene alcohol, and other additives.

The base resin used herein is defined as comprising recurring units (a)having an acid labile group-substituted carboxyl group, preferablyrepresented by the formula (11).

Herein R²¹ is hydrogen or methyl. R²² is an acid labile group. Z is asingle bond or —C(═O)—O—R²³— wherein R²³ is a straight, branched orcyclic C₁-C₁₀ alkylene group in which an ether or ester bond mayintervene in a carbon-carbon bond, or naphthylene group.

Suitable alkylene groups are as exemplified above. Suitable acid labilegroups are those described in JP-A 2014-088557, paragraphs [0039] to[0044] (U.S. Pat. No. 9,017,918).

The base resin may further comprise recurring units (b) having anadhesive group selected from among hydroxyl, lactone ring, ether, ester,carbonyl and cyano groups, for the purpose of improving substrateadhesion to prevent pattern collapse. The base resin may furthercomprise recurring units (c) derived from indene, acenaphthylene,chromone, coumarin, and norbornadiene derivatives, as described in JP-A2012-037867, paragraph [0085]; recurring units (d) derived from styrene,vinylnaphthalene, vinylanthracene, vinylpyrene, and methylene indanederivatives, as described in paragraph [0088]; and/or recurring units(e) derived from onium salts having polymerizable olefin, andfunctioning as acid generator, as described in paragraphs [0089] to[0091].

In the base resin, recurring units (a) are incorporated in an amount ofmore than 0 mol % to 100 mol %, preferably 1 mol % to less than 100 mol%, and more preferably 20 to 90 mol %, based on the entire recurringunits. Recurring units (b) are incorporated in an amount of 0 mol % toless than 100 mol %, preferably 10 to 80 mol %, based on the entirerecurring units. The total of recurring units (a) and (b) is preferably30 to 100 mol %. When recurring units (c) to (e) are incorporated,preferably recurring units (c) are incorporated in an amount of 0 to 40mol %, recurring units (d) are incorporated in an amount of 0 to 20 mol%, recurring units (e) are incorporated in an amount of 0 to 30 mol %,and the total of recurring units (c) to (e) is 0 to 70 mol %.

The base resin should preferably have a Mw in the range of 1,000 to500,000, and more preferably 2,000 to 100,000, as measured by GPC versuspolystyrene standards. If Mw is too low, the diffusion distance of acidgenerated by the acid generator may be extended to invite a drop ofresolution. If Mw is too high, the solubility of the polymer indeveloper may be reduced to invite a drop of resolution.

If a polymer has a wide molecular weight distribution or dispersity(Mw/Mn), which indicates the presence of lower and higher molecularweight polymer fractions, there is a possibility that foreign matter isleft on the pattern or the pattern profile is degraded. The influencesof molecular weight and dispersity become stronger as the pattern rulebecomes finer. Therefore, the base resin should preferably have a narrowdispersity (Mw/Mn) of 1.0 to 2.0, especially 1.0 to 1.5, in order toprovide a resist composition suitable for micropatterning to a smallfeature size.

A blend of two or more polymers which differ in compositional ratio,molecular weight or dispersity is acceptable as the base resin.

The resist composition contains an acid generator such that it mayfunction as a chemically amplified positive resist composition. The acidgenerator is typically a compound capable of generating an acid inresponse to actinic light or radiation, known as photoacid generator(PAG). An appropriate amount of the PAG used is 0.5 to 30 parts, morepreferably 1 to 20 parts by weight per 100 parts by weight of the baseresin. The PAG is any compound capable of generating an acid uponexposure to high-energy radiation. Suitable PAGs include sulfoniumsalts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, andoxime-O-sulfonate acid generators. The acid generators may be used aloneor in admixture of two or more. Exemplary of the acid generated by PAGare sulfonic acids, imidic acids and methide acids. Of these, sulfonicacids which are fluorinated at α-position are most commonly used. Wherethe acid labile group is an acetal group susceptible to deprotection,fluorination at α-position is not always necessary. Where the base resinhas recurring units of acid generator copolymerized therein, the acidgenerator need not be separately added.

Examples of the organic solvent used herein include ketones such ascyclohexanone and methyl-2-n-pentyl ketone; alcohols such as3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether,ethylene glycol monomethyl ether, propylene glycol monoethyl ether,ethylene glycol monoethyl ether, propylene glycol dimethyl ether, anddiethylene glycol dimethyl ether; esters such as propylene glycolmonomethyl ether acetate (PGMEA), propylene glycol monoethyl etheracetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate,tert-butyl propionate, and propylene glycol mono-tert-butyl etheracetate; and lactones such as γ-butyrolactone, and mixtures thereof.Where an acid labile group of acetal form is used, a high-boilingalcohol solvent such as diethylene glycol, propylene glycol, glycerol,1,4-butanediol or 1,3-butanediol may be added for acceleratingdeprotection reaction of acetal.

An appropriate amount of the organic solvent is 100 to 10,000 parts,preferably 300 to 8,000 parts by weight, per 100 parts by weight of thebase resin.

Exemplary basic compounds include primary, secondary and tertiary aminecompounds, specifically amine compounds having a hydroxyl, ether, ester,lactone, cyano or sulfonate group, as described in JP-A 2008-111103,paragraphs [0146] to [0164], and compounds having a carbamate group, asdescribed in JP 3790649. Also, onium salts such as sulfonium salts,iodonium salts and ammonium salts of sulfonic acids which are notfluorinated at a-position as described in US 2008153030 (JP-A2008-158339) and similar onium salts of carboxylic acid as described inJP 3991462 and JP 4226803 may be used as the quencher. They may also beadded to the shrink material.

Where the acid labile group is an acetal group which is very sensitiveto acid, the acid for eliminating the protective group need notnecessarily be a sulfonic acid which is fluorinated at α-position,imidic acid or methide acid. Even with a sulfonic acid which is notfluorinated at α-position, deprotection reaction may take place in somecases. Since an onium salt of sulfonic acid cannot be used as thequencher in this event, an onium salt of imidic acid is preferably usedalone.

An appropriate amount of the basic compound is 0.0001 to 30 parts,preferably 0.001 to 20 parts by weight, per 100 parts by weight of thebase resin.

Exemplary surfactants are described in JP-A 2008-111103, paragraphs[0165]-[0166]. Exemplary dissolution regulators are described in JP-A2008-122932 (US 2008090172), paragraphs [0155]-[0178], and exemplaryacetylene alcohols in paragraphs [0179]-[0182]. The surfactant,dissolution regulator and acetylene alcohol may be used in any suitableamounts, depending on their purpose of addition.

Also a polymeric additive may be added for improving the waterrepellency on surface of a resist film as spin coated. The waterrepellency improver may be used in the topcoatless immersionlithography. The water repellency improver has a specific structure witha 1,1,1,3,3,3-hexafluoro-2-propanol residue and is described in JP-A2007-297590 and JP-A 2008-111103. The water repellency improver to beadded to the resist composition should be soluble in the organic solventas the developer. The water repellency improver of specific structurewith a 1,1,1,3,3,3-hexafluoro-2-propanol residue is well soluble in thedeveloper. A polymer having an amino group or amine salt copolymerizedas recurring units may serve as the water repellent additive and iseffective for preventing evaporation of acid during PEB and avoiding anyhole pattern opening failure after development. An appropriate amount ofthe water repellency improver is 0.1 to 20 parts, preferably 0.5 to 10parts by weight per 100 parts by weight of the base resin.

Pattern Forming Process

Another embodiment is a pattern forming process comprising the steps ofapplying the resist composition onto a substrate, prebaking to form aresist film; exposing the resist film to high-energy radiation, bakingthe film; developing the exposed resist film in an organic solvent-baseddeveloper to form a negative resist pattern; applying the shrinkmaterial onto the negative resist pattern, baking; and removing theexcessive shrink material with an organic solvent.

Referring to FIG. 1(A) to FIG. 1(F), the pattern shrinking process ofthe invention is described. First, as shown in FIG. 1(A), a chemicallyamplified positive resist composition is applied onto a processablesubstrate 20 on a substrate 10 to form a resist film 30 thereon. Ifnecessary, a hard mask layer (not shown) may intervene between theresist film 30 and the processable substrate 20. By standard techniques,the resist film 30 is subjected to exposure (FIG. 1(B)), PEB, andorganic solvent development to form a negative resist pattern 30 a (FIG.1(C)). A shrink material 40 is applied onto the negative resist pattern30 a to cover the pattern as shown in FIG. 1(D). The shrink materialcoating is baked, during which the heat functions to evaporate off thesolvent and to cause the acid to diffuse from the resist pattern 30 ainto the shrink material coating 40. With the acid, the polymer in theshrink material coating undergoes deprotection reaction. Thereafter, asolvent is applied to remove the excessive shrink material 40, leaving ashrink material film over the resist pattern 30 a. This means that theresist pattern 30 a is thickened, that is, the width of spaces in theresist pattern is shrunk as shown in FIG. 1(E). Using the shrunk patternas a mask, the processable substrate 20 is dry etched as shown in FIG.1(F).

The substrate 10 used herein is generally a silicon substrate. Theprocessable substrate (or target film) 20 used herein includes SiO₂,SiN, SiON, SiOC, p-Si, α-Si, TiN, WSi, BPSG, SOG, Cr, CrO, CrON, MoSi,low dielectric film, and etch stopper film. The hard mask may be ofSiO₂, SiN, SiON or p-Si. Sometimes, an undercoat in the form of carbonfilm or a silicon-containing intermediate film may be laid instead ofthe hard mask, and an organic antireflective coating may be interposedbetween the hard mask and the resist film.

While a resist film (30) of a chemically amplified positive resistcomposition is formed on a processable substrate (20) on a substrate(10) directly or via an intermediate intervening layer as mentionedabove, the resist film preferably has a thickness of 10 to 1,000 nm andmore preferably 20 to 500 nm. Prior to exposure, the resist film isheated or prebaked, preferably at a temperature of 50 to 180° C. for 10to 300 seconds, especially at 60 to 150° C. for 15 to 200 seconds.

Next the resist film is exposed to high-energy radiation with wavelength400 nm or shorter or EB. The high-energy radiation is typically i-lineof wavelength 364 nm, KrF excimer laser of wavelength 248 nm, ArFexcimer laser of wavelength 193 nm, or EUV of wavelength 13.5 nm. TheArF 193-nm lithography is most preferred. The exposure may be doneeither in a dry atmosphere such as air or nitrogen stream or byimmersion lithography in water. The ArF immersion lithography usesdeionized water or liquids having a refractive index of at least 1 andhighly transparent to the exposure wavelength such as alkanes as theimmersion solvent. In the immersion lithography, the prebaked resistfilm is exposed to light through a projection lens, with pure water oranother liquid introduced between the resist film and the projectionlens. Since this allows lenses to be designed to a NA of 1.0 or higher,formation of finer feature size patterns is possible. The immersionlithography is important for the ArF lithography to survive to finernode. In the case of immersion lithography, deionized water rinsing (orpost-soaking) may be carried out after exposure for removing waterdroplets left on the resist film, or a protective film may be appliedonto the resist film after pre-baking for preventing any leach-out fromthe resist film and improving water slip on the film surface. The resistprotective film used in the immersion lithography is preferably formedfrom a solution of a polymer having 1,1,1,3,3,3-hexafluoro-2-propanolresidues which is insoluble in water, but soluble in an alkalinedeveloper liquid, in a solvent selected from alcohols of 4 to 10 carbonatoms, ethers of 8 to 12 carbon atoms, and mixtures thereof. Afterformation of the resist film, deionized water rinsing (or post-soaking)may be carried out for extracting the acid generator and the like fromthe film surface or washing away particles, or after exposure, rinsing(or post-soaking) may be carried out for removing water droplets left onthe resist film.

Exposure is preferably performed in an exposure dose of about 1 to 200mJ/cm², more preferably about 10 to 100 mJ/cm². This is followed bybaking (PEB) on a hot plate at 50 to 150° C. for 30 seconds to 5minutes, preferably at 60 to 120° C. for 30 seconds to 3 minutes.

Thereafter the exposed resist film is developed with a developerconsisting of an organic solvent for 0.1 to 3 minutes, preferably 0.5 to2 minutes by any conventional techniques such as dip, puddle and spraytechniques. In this way, a negative resist pattern is formed on thesubstrate. The organic solvent used as developer is preferably selectedfrom among 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone,4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone,methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate,butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate,isopentyl acetate, propyl formate, butyl formate, isobutyl formate,pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate,methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate,ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate,butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate,methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methylbenzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methylphenylacetate, benzyl formate, phenylethyl formate, methyl3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and2-phenylethyl acetate, and mixtures thereof.

At the end of development, the resist film may be rinsed. As the rinsingliquid, a solvent which is miscible with the developer and does notdissolve the resist film is preferred. Suitable solvents includealcohols of 3 to 10 carbon atoms, ether compounds of 8 to 12 carbonatoms, alkanes, alkenes, and alkynes of 6 to 12 carbon atoms, andaromatic solvents. Specifically, suitable alcohols of 3 to 10 carbonatoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol,2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol,2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol,2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol,cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol,3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol,2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol,3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol,4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol,cyclohexanol, and 1-octanol. Suitable alkanes of 6 to 12 carbon atomsinclude hexane, heptane, octane, nonane, decane, undecane, dodecane,methylcyclopentane, dimethylcyclopentane, cyclohexane,methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, andcyclononane. Suitable alkenes of 6 to 12 carbon atoms include hexene,heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene,cycloheptene, and cyclooctene. Suitable alkynes of 6 to 12 carbon atomsinclude hexyne, heptyne, and octyne. Suitable ether compounds of 8 to 12carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butylether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether,di-tert-pentyl ether, and di-n-hexyl ether. Suitable aromatic solventsinclude toluene, xylene, ethylbenzene, isopropylbenzene, t-butylbenzene,and mesitylene. The solvents may be used alone or in admixture. Afterthe rinse liquid is applied, the substrate may be dried by spin dryingand bake. However, rinsing is not essential. As long as the step of spindrying the substrate after the developer is applied thereto is included,the rinsing step may be omitted.

Following the development, the shrink material of the invention isapplied onto the resist pattern to form a shrink material coating,preferably having a thickness of 1 to 150 nm, more preferably 30 to 80nm. The shrink material coating is baked at a temperature of 40 to 180°C. for 5 to 300 seconds. Bake functions to evaporate off the solvent andto induce acid diffusion from the resist film to the shrink material andacid-aided elimination reaction to generate olefin or crosslinkedstructure in the shrink material coating to induce a polarity change,for thereby rendering the shrink material coating insoluble in theorganic solvent.

Finally, the excessive shrink material is removed, preferably using anorganic solvent. Suitable organic solvents which can be used hereininclude propyl acetate, butyl acetate, isobutyl acetate, butenylacetate, pentyl acetate, isopentyl acetate, 2-methylbutyl acetate, hexylacetate, 2-ethylhexyl acetate, cyclohexyl acetate, methylcyclohexylacetate, propyl formate, butyl formate, isobutyl formate, pentylformate, isopentyl formate, hexyl formate, methyl valerate, ethylvalerate, propyl valerate, isopropyl valerate, butyl valerate, isobutylvalerate, tert-butyl valerate, pentyl valerate, isopentyl valerate,ethyl isovalerate, propyl isovalerate, isopropyl isovalerate, butylisovalerate, isobutyl isovalerate, tert-butyl isovalerate, isopentylisovalerate, ethyl 2-methylvalerate, butyl 2-methylvalerate, methylcrotonate, ethyl crotonate, propyl crotonate, isopropyl crotonate, butylcrotonate, t-butyl crotonate, methyl propionate, ethyl propionate,methyl pentenoate, ethyl pentenoate, propyl pentenoate, isopropylpentenoate, butyl pentenoate, t-butyl pentenoate, methyl lactate, ethyllactate, propyl lactate, butyl lactate, isobutyl lactate, pentyllactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl2-hydroxyisobutyrate, ethyl pivalate, propyl pivalate, isopropylpivalate, butyl pivalate, tert-butyl pivalate, butyl propionate,isobutyl propionate, tert-butyl propionate, benzyl propionate, ethyl3-ethoxypropionate, ethyl hexanoate, allyl hexanoate, propyl butyrate,butyl butyrate, isobutyl butyrate, 3-methylbutyl butyrate, tert-butylbutyrate, ethyl 2-methylbutyrate, isopropyl 2-methylbutyrate, methylbenzoate, ethyl benzoate, propyl benzoate, butyl benzoate, phenylacetate, benzyl acetate, methyl phenylacetate, benzyl formate,phenylethyl formate, methyl 3-phenylpropionate, ethyl phenylacetate,2-phenylethyl acetate, 2-heptanone, 3-heptanone, 4-heptanone,2-hexanone, 3-hexanone, 2-octanone, 3-octanone, 4-octanone, 2-nonanone,3-nonanone, 4-nonanone, 5-nonanone, methylcyclohexanone,ethylacetophenone, acetophenone, methylacetophenone, etylacetophenone,ethyl n-butyl ketone, di-n-butyl ketone, diisobutyl ketone, 1-butanol,2-butanol, isobutyl alcohol, t-butyl alcohol, 1-pentanol, 2-pentanol,3-pentanol, t-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol,3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol,2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol,3,3-dimethyl-2-butanol, 2,2-diethyl-1-butanol, 2-methyl-1-pentanol,2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol,3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol,4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and 1-octanol.

The organic solvent used for stripping of the shrink material may beidentical with the organic solvent used as the developer. This meansthat development of the resist film and removal of the shrink materialcan be performed with an identical organic solvent. Advantageously thenozzle needed is only one.

The pattern forming process using the shrink material, when applied to anegative tone resist pattern formed via organic solvent development, issuccessful in reducing the size of holes and/or slits of the negativetone resist pattern in a controlled manner.

EXAMPLE

Examples of the invention are given below by way of illustration and notby way of limitation. The abbreviation “pbw” is parts by weight. For allpolymers, Mw and Mn are determined by GPC versus polystyrene standards.

[1] Synthesis of Polymers Synthesis Example 1

Synthesis of Polymer 1

In nitrogen atmosphere, 37.43 g of 4-acetoxystyrene, 5.85 g ofacenaphthylene, 21.72 g of 4-(1-hydroxy-1-cyclopropyl)styrene, 7.08 g ofdimethyl 2,2′-azobis(2-methyl-propionate) (V-601, Wako Pure ChemicalIndustries, Ltd.), and 60 g of methyl ethyl ketone as solvent were fedinto a 200-mL dropping cylinder to form a monomer solution. A 500-mLflask in nitrogen atmosphere was charged with 48 g of methyl ethylketone, which was heated at 80° C. With stirring, the monomer solutionwas added dropwise to the flask over 4 hours. After the completion ofdropwise addition, the polymerization solution was continuously stirredfor 18 hours while maintaining its temperature at 80° C. Thepolymerization solution was cooled to room temperature, whereupon it wasadded dropwise to 1,000 g of hexane. The precipitated copolymer wascollected by filtration and washed twice with 200 g of hexane. Thecopolymer was dissolved in a mixture of 126 g of tetrahydrofuran and 42g of methanol in a 1-L flask of nitrogen atmosphere, and 16.9 g ofethanolamine was added to the solution, which was stirred at 60° C. for3 hours. The reaction solution was concentrated under reduced pressure.The concentrate was dissolved in a mixture of 300 g of ethyl acetate and80 g of water. The solution was transferred to a separatory funnel, and8.5 g of acetic acid was added thereto, followed by separatoryoperation. The lower layer was discarded. To the organic layer, 80 g ofwater and 11.3 g of pyridine were added, followed by separatoryoperation. The lower layer was discarded. To the organic layer, 80 g ofwater was added, followed by water washing and separatory operation. Thewater washing and separatory operation was repeated 5 times. The organiclayer after separation was concentrated and dissolved in 140 g ofacetone, whereupon the acetone solution was added dropwise to 2,500 g ofwater. The crystallized precipitate was filtered, washed with water, andsuction filtered for 2 hours. The filter cake was dissolved in 150 g ofacetone again, whereupon the acetone solution was added dropwise to2,800 g of water. The crystallized precipitate was filtered, washed withwater, and dried, obtaining 45.0 g of a white polymer. The polymer wasanalyzed by ¹³C-NMR, ¹H-NMR spectroscopy and GPC, with the results shownbelow.

-   -   hydroxystyrene:acenaphthylene:4-(1-hydroxy-1-cyclopropyl)styrene=60.0:10.0:30.0    -   Mw=4,000    -   Mw/Mn=1.66

Synthesis Examples 2 to 22 and Comparative Synthesis Examples 1 to 3

Synthesis of Polymers 2 to 22 and Comparative Polymers 1 to 3

Polymers in Table 1 were prepared by the same procedure as in SynthesisExample 1 aside from changing the type and amount of monomers. Table 1shows the proportion (molar ratio) of units incorporated in the polymer.Tables 2 to 5 show the structure of recurring units.

TABLE 1 Unit Proportion Unit Proportion Unit Proportion Unit Proportion1 (mol %) 2 (mol %) 3 (mol %) 4 (mol %) Mw Mw/Mn Polymer 1 A-1 60 B-1 30C-2 10 4,000 1.66 2 A-1 70 B-1 25 C-1 5 5,300 1.67 3 A-1 70 B-2 25 C-2 54,000 1.63 4 A-1 80 B-3 15 C-2 5 3,900 1.64 5 A-1 75 B-4 20 C-2 5 7,1001.69 6 A-1 60 B-5 30 C-1 10 3,800 1.68 7 A-2 60 B-1 30 C-1 10 4,000 1.648 A-2 65 B-2 30 C-1 5 11,500 1.79 9 A-2 75 B-3 20 C-2 5 4,100 1.66 10A-2 70 B-5 25 C-2 5 4,000 1.65 11 A-2 75 B-6 20 C-2 5 8,400 1.70 12 A-270 B-7 25 C-2 5 4,300 1.63 13 A-3 60 B-1 30 C-2 10 4,400 1.64 14 A-3 65B-2 30 C-1 5 10,000 1.75 15 A-3 75 B-3 15 C-1 10 17,200 1.81 16 A-3 75B-4 20 C-2 5 4,300 1.63 17 A-3 60 B-7 30 C-2 10 4,400 1.64 18 A-3 70 B-825 C-2 5 6,900 1.65 19 A-1 65 B-3 30 C-6 5 7100 1.74 20 A-1 70 B-3 25C-3 5 6,700 1.71 21 A-1 70 B-3 25 C-4 5 7,200 1.68 22 A-1 70 B-3 25 C-55 7,000 1.69 Comparative 1 A-1 60 C-1 10 D-1 30 4,200 1.66 Polymer 2 A-165 C-2 10 D-1 25 4,300 1.66 3 A-1 65 C-2 10 D-2 25 4,300 1.66

TABLE 2

A-1

A-2

A-3

TABLE 3

B-1

B-2

B-3

B-4

B-5

B-6

B-7

B-8

TABLE 4

C-1

C-2

C-3

C-4

C-5

C-6

TABLE 5

D-1

D-2

Synthesis Examples 23, 24

Synthesis of Resist Polymer 1 and Water-Repellent Polymer 1

Polymers were synthesized by combining suitable monomers intetrahydrofuran solvent, effecting copolymerization reaction,crystallizing from methanol, repeatedly washing with hexane, isolationand drying. There were obtained random copolymers, designated ResistPolymer 1 and Water-repellent Polymer 1. The polymers were analyzed by¹H-NMR spectroscopy and GPC. The polymers are identified below withtheir analytical data.

Resist Polymer 1

Mw=7,500

Mw/Mn=1.61

Water-Repellent Polymer 1

Mw=7,800

Mw/Mn=1.55

[2] Preparation of Shrink Material Examples 1 to 42 and ComparativeExamples 1 to 6

A shrink material was prepared by mixing the polymer synthesized above(Polymers 1 to 22 or Comparative Polymers 1 to 3), onium salt, basiccompound, and solvent in accordance with the formulation of Tables 6 and7, and filtering through a Teflon® filter having a pore size of 0.2 μm.Components shown in Tables 6 and 7 are identified below.

TABLE 6 Polymer Additive Organic solvent Shrink material (pbw) (pbw)(pbw) Shrink material 1 Polymer 1 Sulfonium salt 1 4-methyl-2-pentanol(100) (2.0) (3,000) Shrink material 2 Polymer 2 Sulfonium salt 14-methyl-2-pentanol (100) (2.0) (3,000) Shrink material 3 Polymer 3Sulfonium salt 1 4-methyl-2-pentanol (100) (2.0) (3,000) Shrink material4 Polymer 4 Sulfonium salt 1 4-methyl-2-pentanol (100) (2.0) (1,500)butyl acetate (1,500) Shrink material 5 Polymer 5 Sulfonium salt 14-methyl-2-pentanol (100) (2.0) (1,500) butyl acetate (1,500) Shrinkmaterial 6 Polymer 6 Sulfonium salt 1 4-methyl-2-pentanol (100) (2.0)(3,000) Shrink material 7 Polymer 7 Sulfonium salt 1 4-methyl-2-pentanol(100) (2.0) (3,000) Shrink material 8 Polymer 8 Sulfonium salt 14-methyl-2-pentanol (100) (2.0) (1,500) butyl acetate (1,500) Shrinkmaterial 9 Polymer 9 Sulfonium salt 1 4-methyl-2-pentanol (100) (2.0)(1,500) butyl acetate (1,500) Shrink material 10 Polymer 10 Sulfoniumsalt 1 4-methyl-2-pentanol (100) (2.0) (1,500) isopentyl acetate (1,500)Shrink material 11 Polymer 11 Sulfonium salt 1 4-methyl-2-pentanol (100)(2.0) (1,500) butyl acetate (1,500) Shrink material 12 Polymer 12Sulfonium salt 1 4-methyl-2-pentanol (100) (2.0) (1,500) butyl acetate(1,500) Shrink material 13 Polymer 13 Sulfonium salt 14-methyl-2-pentanol (100) (2.0) (3,000) Shrink material 14 Polymer 14Sulfonium salt 1 4-methyl-2-pentanol (100) (2.0) (3,000) Shrink material15 Polymer 15 Sulfonium salt 1 4-methyl-2-pentanol (100) (2.0) (3,000)Shrink material 16 Polymer 16 Sulfonium salt 1 4-methyl-2-pentanol (100)(2.0) (3,000) Shrink material 17 Polymer 17 Sulfonium salt 14-methyl-2-pentanol (100) (2.0) (1,500) butyl acetate (1,500) Shrinkmaterial 18 Polymer 18 Sulfonium salt 1 4-methyl-2-pentanol (100) (2.0)(1,500) butyl acetate (1,500) Shrink material 19 Polymer 19 Sulfoniumsalt 1 2-heptanone (100) (2.0) (3,000) Shrink material 20 Polymer 20Sulfonium salt 1 4-methyl-2-pentanol (100) (2.0) (3,000) Shrink material21 Polymer 21 Sulfonium salt 1 4-methyl-2-pentanol (100) (2.0) (3,000)Shrink material 22 Polymer 22 Sulfonium salt 1 4-methyl-2-pentanol (100)(2.0) (3,000) Shrink material 23 Polymer 1 Sulfonium salt 24-methyl-2-pentanol (100) (2.0) (3,000) Shrink material 24 Polymer 1Sulfonium salt 3 4-methyl-2-pentanol (100) (2.0) (3,000) Shrink material25 Polymer 1 Amine quencher 1 4-methyl-2-pentanol (100) (0.5) (3,000)

TABLE 7 Polymer Additive Organic solvent Shrink material (pbw) (pbw)(pbw) Shrink material 26 Polymer 1 Sulfonium salt 4 4-methyl-2-pentanol(100) (2.0) (1,500) butyl acetate (1,500) Shrink material 27 Polymer 1Sulfonium salt 5 4-methyl-2-pentanol (100) (2.0) (1,500) butyl acetate(1,500) Shrink material 28 Polymer 1 Sulfonium salt 64-methyl-2-pentanol (100) (2.0) (1,500) butyl acetate (1,500) Shrinkmaterial 29 Polymer 1 Sulfonium salt 7 4-methyl-2-pentanol (100) (2.0)(3,000) Shrink material 30 Polymer 1 Sulfonium salt 84-methyl-2-pentanol (100) (2.0) (1,500) butyl acetate (1,500) Shrinkmaterial 31 Polymer 1 Sulfonium salt 9 4-methyl-2-pentanol (100) (2.0)(3,000) Shrink material 32 Polymer 1 Sulfonium salt 104-methyl-2-pentanol (100) (2.0) (3,000) Shrink material 33 Polymer 1Sulfonium salt 11 4-methyl-2-pentanol (100) (2.0) (3,000) Shrinkmaterial 34 Polymer 1 Sulfonium salt 12 4-methyl-2-pentanol (100) (2.0)(3,000) Shrink material 35 Polymer 1 Sulfonium salt 134-methyl-2-pentanol (100) (2.0) (1,500) butyl acetate (1,500) Shrinkmaterial 36 Polymer 1 Sulfonium salt 14 4-methyl-2-pentanol (100) (2.0)(1,500) butyl acetate (1,500) Shrink material 37 Polymer 1 Sulfoniumsalt 15 diisopentyl ether (100) (2.0) (1,000) 2-methyl-2-pentanol(2,000) Shrink material 38 Polymer 1 Iodonium salt 1 4-methyl-2-pentanol(100) (2.0) (1,500) butyl acetate (1,500) Shrink material 39 Polymer 1Ammonium salt 1 4-methyl-2-pentanol (100) (2.0) (1,500) butyl acetate(1,500) Shrink material 40 Polymer 1 Amine quencher 24-methyl-2-pentanol (100) (0.5) (3,000) Shrink material 41 Polymer 14-methyl-2-pentanol (100) (3,000) Shrink material 42 Polymer 44-methyl-2-pentanol (100) (3,000) Comparative Comparative4-methyl-2-pentanol shrink material 1 Polymer 1 (3,000) (100)Comparative Comparative 4-methyl-2-pentanol shrink material 2 Polymer 2(3,000) (100) Comparative Comparative 4-methyl-2-pentanol shrinkmaterial 3 Polymer 3 (3,000) (100) Comparative Comparative Sulfoniumsalt 1 4-methyl-2-pentanol shrink material 4 Polymer 1 (2.0) (3,000)(100) Comparative Comparative Sulfonium salt 1 4-methyl-2-pentanolshrink material 5 Polymer 2 (2.0) (3,000) (100) Comparative ComparativeSulfonium salt 1 4-methyl-2-pentanol shrink material 6 Polymer 3 (2.0)(1,500) (100) diisopentyl ether (1,500)

[3] Preparation of Resist Composition

A resist composition in solution form was prepared by dissolving apolymer (Resist Polymer 1), acid generator, quencher, andwater-repellent polymer in a solvent in accordance with the formulationof Table 8, adding 100 ppm of surfactant FC-4430 (3M) thereto, andfiltering through a filter with a pore size of 0.2 μm. In Table 8, PGMEAis propylene glycol monomethyl ether acetate, and PAG1 is identifiedbelow.

TABLE 8 Acid Water Organic Polymer generator Quencher repellent solventResist (pbw) (pbw) (pbw) (pbw) (pbw) Resist 1 Resist PAG1 Amine Water-PGMEA Polymer 1 (10.0) quencher 1 repellent (2,500) (100) (2.0) Polymer1 γ-butyrolactone (3.0) (200)

[4] ArF Lithography Patterning Test

On a silicon wafer, a spin-on carbon film ODL-101 (Shin-Etsu ChemicalCo., Ltd.) was deposited to a thickness of 180 nm and asilicon-containing spin-on hard mask SHB-A940 was deposited thereon to athickness of 40 nm. On this substrate for trilayer process, the resistcomposition in Table 8 was spin coated, then baked on a hot plate at100° C. for 60 seconds to form a resist film of 90 nm thick. Using anArF excimer laser immersion lithography scanner NSR-610C (Nikon Corp.,NA 1.30, σ 0.90/0.70, annular illumination), the resist film was exposedthrough a 6% halftone phase shift mask while varying the exposure dose.After the exposure, the resist film was baked (PEB) at 90° C. for 60seconds and puddle developed in n-butyl acetate for 30 seconds to form ahole pattern having a hole size of 50 nm and a pitch of 150 nm.

The shrink material shown in Tables 6 and 7 was applied onto the resistpattern after development to cover the pattern. The shrink materialcoating was baked at the temperature shown in Tables 9 and 10 for 60seconds. This was followed by puddle development in 4-methyl-2-pentanolfor 10 seconds to remove the excessive shrink material. Both afterdevelopment and after shrink treatment, the pattern was observed under aCD-SEM (CG-4000 by Hitachi, Ltd.) to measure the size of holes at apitch of 150 nm. The results are shown in Tables 9 and 10.

TABLE 9 Variation Pattern of hole Variation size after size afterPattern of hole removal removal size after size after Bake of shrink ofshrink development development temp. material material Resist (nm) (3σ,nm) Shrink material (° C.) (nm) (3σ, nm) Example 1 Resist 1 52 6.3Shrink material 1 130 29 3.8 (100) 2 Resist 1 50 6.4 Shrink material 2130 27 3.5 (100) 3 Resist 1 51 6.2 Shrink material 3 135 27 3.8 (100) 4Resist 1 52 6.7 Shrink material 4 130 27 3.7 (100) 5 Resist 1 50 6.3Shrink material 5 130 29 4.0 (100) 6 Resist 1 50 6.4 Shrink material 6130 26 3.7 (100) 7 Resist 1 50 6.5 Shrink material 7 130 27 3.9 (100) 8Resist 1 51 6.2 Shrink material 8 130 28 3.9 (100) 9 Resist 1 49 6.6Shrink material 9 130 25 4.0 (100) 10 Resist 1 51 6.4 Shrink material 10135 26 3.6 (100) 11 Resist 1 51 6.5 Shrink material 11 130 26 4.0 (100)12 Resist 1 52 6.1 Shrink material 12 130 27 3.6 (100) 13 Resist 1 516.2 Shrink material 13 135 28 3.6 (100) 14 Resist 1 49 6.3 Shrinkmaterial 14 130 27 3.7 (100) 15 Resist 1 50 6.2 Shrink material 15 13029 3.5 (100) 16 Resist 1 51 6.4 Shrink material 16 130 26 3.6 (100) 17Resist 1 49 6.1 Shrink material 17 135 27 3.4 (100) 18 Resist 1 50 6.5Shrink material 18 130 28 3.6 (100) 19 Resist 1 50 6.2 Shrink material19 130 24 4.7 (100) 20 Resist 1 49 6.1 Shrink material 20 130 27 3.4(100) 21 Resist 1 51 6.3 Shrink material 21 130 26 3.7 (100) 22 Resist 150 6.4 Shrink material 22 130 25 3.5 (100) 23 Resist 1 49 6.1 Shrinkmaterial 23 135 27 3.5 (100) 24 Resist 1 49 6.3 Shrink material 24 13024 4.7 (100) 25 Resist 1 52 6.2 Shrink material 25 130 29 3.9 (100)

TABLE 10 Variation Pattern of hole Variation size after size afterPattern of hole removal removal size after size after Bake of shrink ofshrink development development temp. material material Resist (nm) (3σ,nm) Shrink material (° C.) (nm) (3σ, nm) Example 26 Resist 1 51 6.4Shrink material 26 130 28 3.6 27 Resist 1 51 6.5 Shrink material 27 13028 3.3 28 Resist 1 50 6.0 Shrink material 28 135 28 3.9 29 Resist 1 526.1 Shrink material 29 130 29 3.8 30 Resist 1 49 6.3 Shrink material 30135 26 4.0 31 Resist 1 52 6.5 Shrink material 31 130 26 3.5 32 Resist 149 6.2 Shrink material 32 135 27 3.8 33 Resist 1 50 6.2 Shrink material33 135 25 3.9 34 Resist 1 51 6.2 Shrink material 34 130 26 3.6 35 Resist1 52 6.4 Shrink material 35 130 28 3.9 36 Resist 1 50 6.3 Shrinkmaterial 36 130 28 4.1 37 Resist 1 51 6.4 Shrink material 37 135 25 4.038 Resist 1 52 6.4 Shrink material 38 130 25 4.2 39 Resist 1 50 6.1Shrink material 39 130 27 4.8 40 Resist 1 50 6.3 Shrink material 40 13531 4.9 41 Resist 1 52 6.3 Shrink material 41 130 31 4.8 42 Resist 1 516.0 Shrink material 42 130 24 4.7 Comparative 1 Resist 1 50 6.0Comparative 130 44 11.5 Example shrink material 1 2 Resist 1 51 6.5Comparative 130 44 10.5 shrink material 2 3 Resist 1 48 6.4 Comparative130 33 7.2 shrink material 3 4 Resist 1 50 6.0 Comparative 130 47 7.8shrink material 4 5 Resist 1 50 6.1 Comparative 130 47 7.6 shrinkmaterial 5 6 Resist 1 50 6.2 Comparative 130 38 5.1 shrink material 6

While the invention has been illustrated and described in typicalembodiments, it is not intended to be limited to the details shown,since various modifications and substitutions can be made withoutdeparting in any way from the spirit of the present invention. As such,further modifications and equivalents of the invention herein disclosedmay occur to persons skilled in the art using no more than routineexperimentation, and all such modifications and equivalents are believedto be within the spirit and scope of the invention as defined by thefollowing claims.

Japanese Patent Application Nos. 2014-248080 and 2015-077690 areincorporated herein by reference.

Although some preferred embodiments have been described, manymodifications and variations may be made thereto in light of the aboveteachings. It is therefore to be understood that the invention may bepracticed otherwise than as specifically described without departingfrom the scope of the appended claims.

1. A shrink material comprising a polymer and a solvent containing ananti-vanishing solvent which does not cause a resist pattern afterdevelopment to vanish, said polymer comprising recurring units of atleast one type selected from units having the formulae (1a) and (1b):

wherein A is a single bond or a C₁-C₁₀ alkylene group which may containan ethereal oxygen atom at an intermediate of the chain, R¹ is hydrogen,fluorine, methyl or trifluoromethyl, R² is each independently hydrogen,halogen, an optionally halo-substituted, straight, branched or cyclic,C₂-C₈ acyloxy group, an optionally halo-substituted, straight, branchedor cyclic, C₁-C₆ alkyl group, or an optionally halo-substituted,straight, branched or cyclic, C₁-C₆ alkoxy group, L is hydrogen, astraight, branched or cyclic, C₁-C₁₀ monovalent aliphatic hydrocarbongroup which may contain an ethereal oxygen atom, carbonyl moiety orcarbonyloxy moiety at an intermediate of the chain, or an optionallysubstituted, monovalent aromatic ring-containing group, Z bonds with thecarbon atom to form a C₅-C₁₅ alicyclic group, R^(x) and R^(y) are eachindependently hydrogen or a straight, branched or cyclic, C₁-C₁₅ alkylgroup which may be substituted with a hydroxyl or alkoxy moiety, atleast one of R^(x) and R^(y) being a cyclic C₅-C₁₅ alkyl group, f is aninteger of 1 to 3, s is an integer of 0 to 2, a is equal to (5+2s−f),and m is 0 or
 1. 2. The shrink material of claim 1 wherein said polymerfurther comprises recurring units having the formula (2):

wherein B is a single bond or a C₁-C₁₀ alkylene group which may containan ethereal oxygen atom at an intermediate of the chain, R¹ is asdefined above, R³ is each independently hydrogen, halogen, an optionallyhalo-substituted, straight, branched or cyclic, C₂-C₈ acyloxy group, anoptionally halo-substituted, straight, branched or cyclic, C₁-C₆ alkylgroup, or an optionally halo-substituted, straight, branched or cyclic,C₁-C₆ alkoxy group, g is an integer of 0 to 3, t is an integer of 0 to2, b is equal to (5+2t−g), and n is 0 or
 1. 3. The shrink material ofclaim 1 wherein said polymer further comprises recurring units havingthe formula (3):

wherein C is a single bond or a C₁-C₁₀ alkylene group which may containan ethereal oxygen atom at an intermediate of the chain, R¹ is asdefined above, R⁴ is each independently hydrogen, halogen, an optionallyhalo-substituted, straight, branched or cyclic, C₂-C₈ acyloxy group, anoptionally halo-substituted, straight, branched or cyclic, C₁-C₆ alkylgroup, or an optionally halo-substituted, straight, branched or cyclic,C₁-C₆ alkoxy group, D is a single bond or a straight, branched orcyclic, C₁-C₁₀ (v+1)-valent hydrocarbon group which may contain anethereal oxygen atom, carbonyl moiety or carbonyloxy moiety at anintermediate of the chain, in which some or all carbon-bonded hydrogenatoms may be substituted by fluorine, Rf¹ and Rf² are each independentlya C₁-C₆ alkyl group containing at least one fluorine atom, Rf' may bondwith D to form a ring with the carbon atoms to which they are attached,r is 0 or 1, h is an integer of 1 to 3, u is an integer of 0 to 2, c isequal to (5+2u−h), and v is 1 or
 2. 4. The shrink material of claim 1wherein said polymer further comprises recurring units of at least onetype selected from units having the formulae (4) and (5):

wherein R⁵ and R⁶ are each independently hydrogen, halogen, anoptionally halo-substituted, straight, branched or cyclic, C₂-C₈ acyloxygroup, an optionally halo-substituted, straight, branched or cyclic,C₁-C₆ alkyl group, or an optionally halo-substituted, straight, branchedor cyclic, C₁-C₆ alkoxy group, i and j are each independently an integerof 0 to 2, d is equal to (6−i), and e is equal to (4−j).
 5. The shrinkmaterial of claim 1 wherein said polymer further comprises recurringunits of at least one type selected from units having the formulae (A)to (E):

wherein R¹ is as defined above, X^(A) is an acid labile group, X^(B) andX^(C) are each independently a single bond or a straight or branchedC₁-C₄ divalent hydrocarbon group, X^(D) is a straight, branched orcyclic, C₁-C₁₆ di- to pentavalent aliphatic hydrocarbon group in whichany constituent —CH₂— may be substituted by —O— or —C(═O)—, X^(E) is anacid labile group, Y^(A) is a substituent group having a lactone,sultone or carbonate structure, Z^(A) is hydrogen, a C₁-C₃₀ fluoroalkylgroup or a C₁-C₁₅ fluoroalcohol-containing substituent group, k^(1A) isan integer of 1 to 3, and k^(1B) is an integer of 1 to
 4. 6. The shrinkmaterial of claim 1 wherein said polymer further comprises recurringunits having the formula (F):

wherein R¹⁰¹ is hydrogen or methyl, X is a single bond, —C(═O)—,—C(═O)—O— or —C(═O)—NH—, R¹⁰² is a single bond or a straight, branchedor cyclic C₁-C₁₀ alkylene group which may contain an ether, ester,carbonyl moiety, —N═ or —S—, or a phenylene or naphthylene group, R¹⁰³and R¹⁰⁴ are each independently hydrogen, a straight or branched C₁-C₄alkyl group, or an acid labile group, or R¹⁰³ and R¹⁰⁴ may bond togetherto form a ring with the nitrogen atom to which they are attached, thering optionally containing an ether bond, or either one of R¹⁰³ and R¹⁰⁴may bond with R¹⁰² to form a ring with the nitrogen atom to which theyare attached, and k^(1C) is 1 or
 2. 7. The shrink material of claim 1,further comprising a salt having the formula (9):R¹¹—CO₂ ⁻M⁺  (9) wherein R¹¹ is a straight, branched or cyclic C₁-C₂₀alkyl group, straight, branched or cyclic C₂-C₂₀ alkenyl group or C₆-C₂₀monovalent aromatic ring-containing group, in which some or allcarbon-bonded hydrogen atoms may be substituted by fluorine, lactonering-containing moiety, lactam ring-containing moiety or hydroxylmoiety, and in which an ether, ester or carbonyl moiety may intervene ina carbon-carbon bond, and M^(*) is a sulfonium, iodonium or ammoniumcation.
 8. The shrink material of claim 1, further comprising a salthaving the formula (10):R¹²—SO₃ ⁻M⁺  (10) wherein R¹² is a straight, branched or cyclic C₁-C₃₅monovalent hydrocarbon group which may contain an oxygen atom, in whichsome or all carbon-bonded hydrogen atoms may be substituted by fluorine,with the proviso that the hydrogen atom bonded to the carbon atom ata-position relative to sulfonic acid is not substituted by fluorine, andM⁺ is a sulfonium, iodonium or ammonium cation.
 9. The shrink materialof claim 1, further comprising at least one basic compound selected fromthe group consisting of primary, secondary and tertiary aliphaticamines, mixed amines, aromatic amines, heterocyclic amines,nitrogen-containing compounds having carboxyl group, nitrogen-containingcompounds having sulfonyl group, nitrogen-containing compounds havinghydroxyl group, nitrogen-containing compounds having hydroxyphenylgroup, alcoholic nitrogen-containing compounds, amide derivatives, imidederivatives, and carbamates.
 10. The shrink material of claim 1 whereinthe anti-vanishing solvent is an ester solvent of 7 to 16 carbon atoms,ketone solvent of 8 to 16 carbon atoms, or alcohol solvent of 4 to 10carbon atoms.
 11. The shrink material of claim 10 wherein theanti-vanishing solvent is at least one solvent selected from the groupconsisting of: ester solvents of 7 to 16 carbon atoms including pentylacetate, isopentyl acetate, 2-methylbutyl acetate, hexyl acetate,2-ethylhexyl acetate, cyclohexyl acetate, methylcyclohexyl acetate,hexyl formate, ethyl valerate, propyl valerate, isopropyl valerate,butyl valerate, isobutyl valerate, tert-butyl valerate, pentyl valerate,isopentyl valerate, ethyl isovalerate, propyl isovalerate, isopropylisovalerate, butyl isovalerate, isobutyl isovalerate, tert-butylisovalerate, isopentyl isovalerate, ethyl 2-methylvalerate, butyl2-methylvalerate, ethyl pivalate, propyl pivalate, isopropyl pivalate,butyl pivalate, tert-butyl pivalate, ethyl pentenoate, propylpentenoate, isopropyl pentenoate, butyl pentenoate, tert-butylpentenoate, propyl crotonate, isopropyl crotonate, butyl crotonate,tert-butyl crotonate, butyl propionate, isobutyl propionate, tert-butylpropionate, benzyl propionate, ethyl hexanoate, allyl hexanoate, propylbutyrate, butyl butyrate, isobutyl butyrate, 3-methylbutyl butyrate,tert-butyl butyrate, ethyl 2-methylbutyrate, isopropyl 2-methylbutyrate,methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, phenylacetate, benzyl acetate, methyl phenylacetate, benzyl formate,phenylethyl formate, methyl 3-phenylpropionate, ethyl phenylacetate, and2-phenylethyl acetate, ketone solvents of 8 to 16 carbon atoms including2-octanone, 3-octanone, 4-octanone, 2-nonanone, 3-nonanone, 4-nonanone,5-nonanone, diisobutyl ketone, ethylcyclohexanone, ethylacetophenone,ethyl n-butyl ketone, di-n-butyl ketone, and diisobutyl ketone, andalcohol solvents of 4 to 10 carbon atoms including 1-butanol, 2-butanol,isobutyl alcohol, t-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol,t-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol,3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol,2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol,3,3-dimethyl-2-butanol, 2,2-diethyl-1-butanol, 2-methyl-1-pentanol,2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol,3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol,4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and 1-octanol.12. The shrink material of claim 1 wherein said solvent contains theanti-vanishing solvent and an additional solvent, the additional solventbeing selected from the group consisting of 2-octanone, 2-nonanone,2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone,diisobutyl ketone, methylcyclohexanone, acetophenone,methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate,pentyl acetate, isopentyl acetate, butenyl acetate, propyl formate,butyl formate, isobutyl formate, pentyl formate, isopentyl formate,methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate,methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyllactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate,pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate,benzyl acetate, methyl phenylacetate, benzyl formate, phenylethylformate, methyl 3-phenylpropionate, benzyl propionate, ethylphenylacetate, and 2-phenylethyl acetate.
 13. A pattern forming processcomprising the steps of: applying a resist composition onto a substrate,said resist composition comprising a base resin comprising recurringunits having an acid labile group-substituted carboxyl group, an acidgenerator and an organic solvent, prebaking to form a resist film,exposing the resist film to high-energy radiation, baking the film,developing the exposed resist film in an organic solvent-based developerto form a negative resist pattern, applying the shrink material of claim1 onto the negative resist pattern, baking, and removing the excessiveshrink material with an organic solvent.
 14. The pattern forming processof claim 13 wherein the base resin in the resist composition comprisesrecurring units (a) having an acid labile group-substituted carboxylgroup, represented by the formula (11):

wherein R²¹ is hydrogen or methyl, R²² is an acid labile group, Z is asingle bond or —C(═O)—O—R²³—, and R²³ is a straight, branched or cyclicC₁-C₁₀ alkylene group in which an ether or ester bond may intervene in acarbon-carbon bond, or naphthylene group.
 15. The pattern formingprocess of claim 13 wherein the developer comprises at least one organicsolvent selected from the group consisting of 2-octanone, 2-nonanone,2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone,diisobutyl ketone, methylcyclohexanone, acetophenone,methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate,pentyl acetate, isopentyl acetate, butenyl acetate, propyl formate,butyl formate, isobutyl formate, pentyl formate, isopentyl formate,methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate,methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyllactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate,pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate,benzyl acetate, methyl phenylacetate, benzyl formate, phenylethylformate, methyl 3-phenylpropionate, benzyl propionate, ethylphenylacetate, and 2-phenylethyl acetate.
 16. The pattern formingprocess of claim 13 wherein the step of removing the excessive shrinkmaterial uses at least one organic solvent selected from the groupconsisting of propyl acetate, butyl acetate, isobutyl acetate, butenylacetate, pentyl acetate, isopentyl acetate, 2-methylbutyl acetate, hexylacetate, 2-ethylhexyl acetate, cyclohexyl acetate, methylcyclohexylacetate, propyl formate, butyl formate, isobutyl formate, pentylformate, isopentyl formate, hexyl formate, methyl valerate, ethylvalerate, propyl valerate, isopropyl valerate, butyl valerate, isobutylvalerate, tert-butyl valerate, pentyl valerate, isopentyl valerate,ethyl isovalerate, propyl isovalerate, isopropyl isovalerate, butylisovalerate, isobutyl isovalerate, tert-butyl isovalerate, isopentylisovalerate, ethyl 2-methylvalerate, butyl 2-methylvalerate, methylcrotonate, ethyl crotonate, propyl crotonate, isopropyl crotonate, butylcrotonate, tert-butyl crotonate, methyl propionate, ethyl propionate,ethyl pentenoate, propyl pentenoate, isopropyl pentenoate, butylpentenoate, tert-butyl pentenoate, methyl lactate, ethyl lactate, propyllactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyllactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, ethylpivalate, propyl pivalate, isopropyl pivalate, butyl pivalate,tert-butyl pivalate, butyl propionate, isobutyl propionate, tert-butylpropionate, benzyl propionate, ethyl 3-ethoxypropionate, ethylhexanoate, allyl hexanoate, propyl butyrate, butyl butyrate, isobutylbutyrate, 3-methylbutyl butyrate, tert-butyl butyrate, ethyl2-methylbutyrate, isopropyl 2-methylbutyrate, methyl benzoate, ethylbenzoate, propyl benzoate, butyl benzoate, phenyl acetate, benzylacetate, methyl phenylacetate, benzyl formate, phenylethyl formate,methyl 3-phenylpropionate, ethyl phenylacetate, 2-phenylethyl acetate,2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone,2-octanone, 3-octanone, 4-octanone, 2-nonanone, 3-nonanone, 4-nonanone,5-nonanone, methylcyclohexanone, ethylcyclohexanone, acetophenone,methylacetophenone, ethylacetophenone, ethyl n-butyl ketone, di-n-butylketone, diisobutyl ketone, 1-butanol, 2-butanol, isobutyl alcohol,t-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, t-pentyl alcohol,neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol,3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol,2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol,2,2-diethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol,2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol,3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol,4-methyl-3-pentanol, cyclohexanol, and 1-octanol.
 17. The patternforming process of claim 13 wherein the high-energy radiation is i-lineof wavelength 364 nm, KrF excimer laser of wavelength 248 nm, ArFexcimer laser of wavelength 193 nm, EUV of wavelength 13.5 nm, or EB.